• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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    • 专利摘要:
    The invention relates to a radiation conversion device (910), such as a photovoltaic cell, a photodiode or a semiconductor radiation detection device, comprising a semiconductor subregion (100) with first compensation duties (111) of a first conductivity type and a base subregion (120) comprising the first compensation zones (111). separates each other. The first compensation zones (111) are arranged in pillar structures (110). Each pillar structure (110) includes spatially separated first compensation zones (111) and extends in a vertical direction with respect to a main surface (101) of the semiconductor subregion (100). Between adjacent ones of the pillar structures (110), the base portion (120) includes second compensation zones (122) of a second complementary conductivity type. The radiation conversion device combines high radiation hardness with cost-effective production.
    公开号:CH707923B1
    申请号:CH00602/14
    申请日:2014-04-17
    公开日:2018-10-31
    发明作者:Willmeroth Armin；Hans-Joachim Schulze Dr
    申请人:Infineon Technologies Austria Ag；
    IPC主号:
    专利说明:

    Description In radiation conversion devices, incident radiation generates electron-hole pairs by lifting electrons from the valence band into the conduction band. The generated electron-hole pairs are separated according to their polarity and travel to the corresponding electrodes, where they induce an electric current. The radiation conversion mechanism can be used in semiconductor radiation detectors, photovoltaic cells and photodetectors. It is desirable to provide improved radiation conversion devices. The object is achieved by the teaching of the independent claims. Further developments are the subject of the dependent claims,
    SUMMARY [0002] According to the invention, a radiation conversion device comprises a semiconductor subregion having first compensation zones of a first conductivity type and a base subregion separating the first compensation zones. The first compensation zones are arranged in columnar structures, each columnar structure comprising at least two of the first compensation zones, and extend in a vertical direction with respect to a main surface of the semiconductor subarea. Between adjacent ones of the pillar structures, the base portion includes second compensation zones of a second conductivity type that is complementary to the first conductivity type.
    A radiation conversion device according to one embodiment comprises a semiconductor subregion with first compensation zones arranged in strip-shaped column structures of a first conduction type and between adjacent column structures second compensation zones of a second, complementary conduction type. Each pillar structure includes at least two of the first compensation zones, and extends in a vertical direction and a first lateral direction with respect to a main surface of the semiconductor subregion. A first electrode structure having a plurality of stripes directly adjoins the semiconductor portion. Each strip is associated with at least two of the columnar structures.
    A radiation conversion device according to another embodiment comprises a semiconductor subregion having first compensation regions of a first conductivity type and a base subregion. The first compensation zones are arranged in columnar structures, with each columnar structure extending in a vertical direction with respect to the main surface of the semiconductor subregion. The base portion includes a background portion and second compensation zones of a second, complementary type of conduction between adjacent ones of the columnar structures. The second compensation zones form further column structures extending in the vertical direction. Vertical dopant profiles of the second compensation zones are Gaussian distributions.
    According to the invention, a method for manufacturing a radiation conversion device comprises epitaxially growing a sequence of semiconductor layers on a semiconductor substrate. In at least two of the semiconductor layers, dopants of a first conductivity type are introduced into exposed first sections of a process surface of a preceding one of the semiconductor layers before the subsequent growth of the semiconductor layers to the preceding one. The semiconductor layers are annealed to form first compensation zones of the introduced dopants. Annealing is discontinued before the first compensation zones structurally bond together. Those skilled in the art will recognize additional features and advantages upon reading the following detailed description and upon considering the accompanying drawings.
    Brief Description of the Drawings The accompanying drawings are for further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the invention and, together with the description, serve to explain the principles of the invention. Other embodiments of the present invention and many of the intended advantages of the present invention will be more readily appreciated as they become better understood by reference to the following detailed description.
    FIG. 1A is a simplified block diagram of a radiation detection apparatus according to one embodiment. FIG.
    Fig. 1B is a simplified block diagram of a solar generator device according to another embodiment form.
    FIG. 1C is a schematic cross-sectional view of a portion of a radiation conversion apparatus according to an embodiment. FIG.
    2A is a schematic cross-sectional view of a portion of a radiation conversion device according to an embodiment providing a uniformly n-doped base portion,
    Fig. 2B is a schematic diagram of the charge carrier distribution in the radiation conversion device of Fig. 2A with no voltage applied between the electrodes.
    Fig. 2C is a schematic diagram of the charge carrier distribution in the radiation conversion device of Fig. 2A in the reverse biased state.
    FIG. 2D is a schematic cross-sectional view of a portion of a radiation conversion device according to an embodiment providing a uniformly p-doped base portion. FIG.
    3A is a schematic cross-sectional view of a portion of a radiation conversion device according to an embodiment providing implanted first and second compensation zones.
    FIG. 3B is a schematic graphical representation of the electric field profiles in the radiation conversion device of FIG. 3A with no voltage applied between the electrodes. FIG.
    FIG. 3C is a schematic diagram of the electric field profiles in the radiation conversion device of FIG. 3A in a backward biased condition. FIG.
    4A is a schematic cross-sectional view of a portion of a radiation conversion device according to an embodiment providing spatially separated implanted compensation zones of the two dopant types.
    4B is a schematic cross-sectional view of a portion of a radiation conversion device according to an embodiment providing associated implanted compensation zones of both dopant types.
    4C is a schematic cross-sectional view of a portion of a radiation conversion device according to an embodiment providing p and n electrodes on the same side.
    5A is a schematic plan view of a portion of a radiation conversion device according to an embodiment providing an electrode with a single strip associated with two pillar structures.
    FIG. 5B is a schematic cross-sectional view of the radiation conversion device of FIG. 5A; FIG.
    6 is a schematic plan view of a portion of a radiation conversion device according to an embodiment providing an electrode with stripes crossing strip-shaped column structures.
    7 is a schematic cross-sectional view of a semiconductor substrate for illustrating a method of manufacturing a radiation conversion device according to an embodiment after introducing the dopants into portions of an epitaxially grown first semiconductor layer.
    FIG. 7B is a schematic cross-sectional view of the semiconductor substrate of FIG. 7A after growing a sequence of semiconductor layers. FIG.
    FIG. 7C is a schematic cross-sectional view of the semiconductor substrate of FIG. 7B after annealing. FIG.
    8A is a schematic cross-sectional view of a semiconductor substrate for illustrating a method of manufacturing a radiation conversion device according to an embodiment after inserting the dopants of both types into portions of an epitaxial grown first semiconductor layer.
    FIG. 8B is a schematic cross-sectional view of the semiconductor substrate of FIG. 8A after growing a sequence of semiconductor layers. FIG.
    FIG. 8C is a schematic cross-sectional view of the semiconductor substrate of FIG. 8B after annealing. FIG.
    9 is a simplified flowchart of a method of manufacturing a radiation conversion apparatus according to another embodiment.
    DETAILED DESCRIPTION In the following detailed description, reference is made to the accompanying drawings, which form a part of the disclosure, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. For example, features illustrated or described for one embodiment may be used in or in connection with other embodiments to yield yet a further embodiment. It is intended that the present invention include such modifications and alterations. The examples are described by means of a specific language, which should not be construed as limiting the scope of the appended claims. The drawings are not to scale and are for illustration purposes only. For the sake of clarity, corresponding elements will be denoted by the same reference numerals in the various drawings unless otherwise stated.
    The terms "having," "including," "comprising," "having," and similar terms are open-ended terms, and these terms indicate the presence of the specified structures, elements, or features, but do not preclude additional elements or features , The indefinite and definite articles include the plural as well as the singular, unless the context clearly dictates otherwise.
    The term or term "electrically connected" describes a low-resistance connection between the electrically connected elements, for example, a direct contact between the elements in question or a connection via a metal and / or a heavily doped semiconductor. The term "electrically coupled" implies that one or more intermediate and suitable for signal transmission elements between the "electrically coupled" elements may be present, for example. Elements that are controllable so that they temporarily a low-impedance connection in a first state and can produce a high-impedance decoupling in a second state.
    For example, "n-" means a doping concentration that is less than the doping concentration of an "n" doping zone, while an "n +" means Doping zone has a larger doping concentration than the "n" doping zone. However, the indication of the relative doping concentration does not mean that doping zones having the same relative doping concentration must have the same absolute doping concentration, unless otherwise stated. For example, two different "n" zones may have the same or different absolute doping concentrations.
    FIG. 1A shows a radiation meter 901 based on a semiconductor radiation conversion device 910 designed as a radiation detection device. The radiation conversion device 910 may be a backward biased semiconductor diode that is operated in the non-conductive state. A DC voltage source 940 and an amplifier circuit 920 may be electrically coupled to the electrodes of the radiation conversion device. An evaluation unit 930 may be electrically coupled to the output terminal of the amplifier circuit 920.
    The DC power source 940 biases the semiconductor conversion device 910 backward and generates a depletion zone in the radiation conversion device 910. Incident radiation 9S0 is incident on a radiation-receiving surface of the radiation conversion device 910. The incident radiation 990 may be ionizing radiation, for example gamma radiation, beta radiation or x-radiation, or non-ionizing radiation, for example ultraviolet light, visible light or infrared light and generates electron hole pairs. In the depletion zone, the generated electrons and holes migrate to the corresponding electrodes and induce a current pulse between the electrodes. The amplifier circuit 920 may amplify the induced current and the evaluation unit 930 may further process and analyze the amplified current.
    The sensitivity of the radiation detection device 910 can be increased by a cooling device that reduces the intrinsic carrier density and / or by applying a comparatively high voltage between the electrodes so that the accelerated electrons trigger the generation of further electron-hole pairs. Each of the electrodes may be split and read out differently to obtain location information regarding the incident radiation.
    FIG. 1B relates to a solar generator device 902 that uses a photovoltaic cell-configured radiation conversion device 910. The output current of the radiation conversion device may be fed to a charge controller 950 which controls the charging of a backup battery 960 or supplies power to a payload 970, e.g. Fig. 1C relates to a radiation conversion device 910 which may be formed as a photovoltaic cell, a photodiode or a radiation detection device. The radiation conversion device 910 includes a semiconductor portion 100 formed of single crystal semiconductor material. According to one embodiment, the semiconductor material is a silicon crystal (Si), a germanium crystal (Ge), a silicon carbide crystal (SiC) or a silicon germanium crystal (SiGe). According to a further embodiment, the monocrystalline semiconductor material may be gallium nitride (GaN) or gallium arsenide (GaAs), for example.
    The semiconductor subregion 100 has a main surface 101 and a back surface 102 that is substantially parallel to the main surface 101. The distance between the main surface 101 and the back surface 102 may be between 50 μm and several mm. A silicon-based radiation detection device may have a thickness of at least 150 pm and a maximum of 400 pm, for example about 250 pm. The shape of the semiconductor portion 100 may be a rectangle having an edge length in the range of several mm or a circle having a diameter of several mm. The normal to the main surface 101 defines a vertical direction, and directions orthogonal to the normal direction are lateral directions.
    The semiconductor subregion 100 includes first compensation regions 111 of a first conductivity type arranged in pillar structures 110. Each pillar structure 110 extends in a vertical direction and includes at least two first compensation zones 111. Some or all of the first compensation zones 111 of a pillar structure 110 are spatially separated.
    A base portion 120 separates the first compensation zones 111 from each other. The base portion 120 includes second compensation zones 122 of a second conductivity type that is complementary to the first conductivity type. The second compensation zones 122 are formed between adjacent columnar structures 110. The base portion 120 also includes portions 121 that separate the first compensation zones 101 in the vertical direction.
    The portions 121 may have the second conductivity type, which is opposite to the conductivity type of the first compensation zones 111. For example, the base portion 120 including the portions 121 and the second compensation zones 122 may have a uniform background dopant concentration. According to other embodiments, the portions 121 of the base portion 120 have the same conductivity type as the first compensation zones 111, but differ significantly from the first compensation zones 111 with respect to the impurity concentration and the impurity profile.
    For example, the portions 121 of the base portion 120 separating the first compensation zones 111 in a vertical direction may have a mean net dopant concentration so that they are completely depleted in an operating condition, for example, by applying reverse bias of at least 10 V. The average net dopant concentration in the first compensation zones 111 is at least 20 times or even at least 40 times greater than the average dopant concentration in the sections 121 of the base section 120.
    The vertical dopant profile of the portions 121 of the base portion 120 may differ significantly from the vertical dopant profile in the first compensation zones 111. For example, the vertical dopant profiles of the first compensation zones 111 may approximate Gaussian distributions, whereas the dopant distribution in the sections 121 is approximately uniform.
    When the radiation conversion device 910 is biased backward, the electric field applied between the first and second compensation zones 111, 122 depletes a majority of the semiconductor region 101 even with a background dopant concentration present in the base region 120, which is less than an intrinsic layer of a pin Diode is high. The increased background dopant concentration increases device robustness with respect to radiation damage, which gradually shifts the net dopant concentration to a higher acceptor concentration so that only a smaller portion of an original detection volume can be depleted. While conventional radiation conversion devices based on pin diodes gradually lose sensitivity because the depleted portion shrinks, the long-term influence of radiation damage on the sensitivity of radiation conversion device and the efficiency of photovoltaic cells based on the compensation zones 111 is low.
    Compared to approaches using columnar structures with associated compensation zones, significantly fewer epitaxial layers and / or shorter annealing times are needed to diffuse the implanted dopants. The fabrication of the radiation conversion device 910 is significantly simplified and more cost effective.
    In Figs. 2A to 2D, a semiconductor subregion 100 of a radiation conversion device 910 has a main surface 101, which may be the radiation-receiving surface, and a back surface 102, parallel to the main surface 101. The semiconductor subregion 100 may have a rectangular or circular shape. Column structures 110 extend in the vertical direction between the main surface 101 and the back surface 102. The pillar structures 110 may be, for example, pillared or strip-like. According to one embodiment, a cross section of the pillar structures 110 parallel to the main surface 101 is a circle, an oval, an ellipse or a rectangle, for example a square with rounded corners. According to the illustrated embodiment, the pillar structures 110 are strip-shaped and, in a first lateral direction parallel to the main surface 101, have a length that is significantly greater than a width in a second lateral direction orthogonal to the first lateral direction.
    Each pillar structure 101 includes two or more first compensation zones 111 that are spatially separated from each other. The first compensation zones 111 have the first conductivity type and are embedded in a base portion 120. Portions of the base portion 120 between adjacent column structures 110 provide second compensation zones 122 of a second power type opposite to the first conductivity type. Further portions 121 of the base portion 120 divide the first compensation zones 111 along the vertical direction.
    The dopants or net dopants in the first compensation zone 111 compensate the dopants of the second compensation zones 122 such that the regions between adjacent column structures 110 can be completely depleted by applying a sufficiently high reverse blocking voltage. The resulting depletion zones represent the detection volume in which the incident radiation generates free charge carriers and the free charge carriers are transported to the corresponding electrodes.
    The required operating reverse blocking voltage (detection voltage) depends on the dopant concentration in the and the dimension of the first and second compensation zones 111, 122.
    According to one embodiment, the dopant charge of the first conductivity type in the first compensation zones 111 is higher than the dopant charge of the second conductivity type in the second compensation zones 122. In a plane parallel to the main surface 101 and intersecting the first compensation zones 111, the number of dopant atoms of the first exceeds Conductivity type, the number of dopant atoms of the second conductivity type.
    A typical detection voltage, which is typically between 5% and 95% of the breakdown voltage, completely depletes the second compensation zones 122, but does not completely deplete the first compensation zones 111. The detection voltage and the lateral extent of the first compensation zones 111 can be adjusted so that the lateral width of the remaining non-depleted partial area of the first compensation zones 111 is smaller than a charge carrier diffusion length prevailing in the first compensation zones 111. The width of the non-depleted portion may be, for example, less than 50% of the diffusion length or less than 10% of the diffusion length. In this way, recombination of radiation-generated free charge carriers in the first compensation zones 111 is minimized and the detection sensitivity is maximized.
    For example, a ratio between an average net dopant concentration in the first compensation zones 111 and an average net dopant concentration in the second compensation zones 122 may be between 2 and 105, wherein according to one embodiment, the dopant concentration in the base portion 120 is at least 1.5 x 10 13 cm -3 or even 5 x 1013cm-3 for Si, or at least 2, 5x1014cm-3 for Ge and at most 1.5x1017cm-3 for Si and at most 2.5x1017cm-3 for Ge. The pillar structures 110 may be evenly spaced. For a silicon device, the distance d between the center of the adjacent columnar structures 110 may be between 10 pm and 200 pm, for example between 20 pm and 160 pm.
    A first electrode structure 210 is disposed in direct contact with the main surface 101 and abuts directly on the semiconductor portion 100. The first electrode structure 210 may be a continuous, uniform layer covering a closed portion of the main surface 101. According to a further embodiment, the first electrode structure 210 comprises a plurality of strips, each strip being associated with one or more columnar structures 210 such that the corresponding strip supplies the associated columnar structures 110 with a potential applied to the first electrode structure when the detection voltage is applied.
    According to the illustrated embodiment, each individual strip is associated with a single columnar structure 110. According to further embodiments, each of the individual strips is associated with at least two of the column structures. According to further embodiments, the strips extend in a second lateral direction intersecting the first lateral direction. For example, the second lateral direction is orthogonal to the first lateral direction.
    Heavily doped first contact regions 118 of the first conductivity type are provided in portions of the semiconductor portion 100 directly adjacent to the first electrode structure 210 to form a low-resistance contact (Schottky contact) between the first electrode pattern 210 and the semiconductor portion 100. For p-type silicon (p-Si), the dopant concentration in the first contact zones 1.18 is for example at least 1016 cm-3 and for n-type silicon (n-Si) at least 3 × 1019 cm-3.
    The first contact zones 118 may be aligned along the pillar structures 110. For example, each contact zone 118 may be disposed entirely in the vertical projection of one of the pillar structures 110. According to another embodiment, some or all of the contact zones 118 overlap only partially with the vertical projection of the one, two or more columnar structures 110. The first contact zones 118 may be spaced from or overlapping the next first compensation zones 111.
    The semiconductor subregion 100 includes one or more second contact regions 128 of the second conductivity type that are directly adjacent to the rear side surface 102. The second contact zones 128 provide ohmic contact to a second electrode structure 220. The second electrode structure 220 may cover a closed surface of the backside surface 102. According to other embodiments, the second electrode structure may comprise strips, each strip partially or completely overlapping the vertical projection of at least one of the second compensation zones 122.
    Each of the first and second electrode structures 210, 220 may comprise one or more layers, wherein each layer may comprise aluminum Al, copper Cu or an aluminum-copper alloy, for example AICu or AlSiCu. According to further embodiments, at least one of the first electrode structures 210, 220 is provided of a transparent conductive material, for example a tin oxide. At least one of the first and second electrode structures 210, 220 may comprise one or more layers containing as main constituents nickel Ni, gold Au, silver Ag, titanium Ti, tantalum Ta or palladium Pd.
    The base portion 120, which includes the second compensation zones 122 and the portions 121 separating the first compensation zones 111 in the vertical direction, has an approximately uniform dopant distribution. Vertical dopant profiles of the first compensation zones 111 are approximately Gaussian distributions. According to the illustrated embodiment, the first conductivity type is p-type and the second conductivity type is n-type.
    Fig. 2B shows the charge carrier distribution in the radiation conversion device 910 of Fig. 2A at rest with no reverse reverse voltage applied. FIG. 2C shows the charge carrier distribution with a sufficiently high reverse blocking voltage applied between the first and second electrode structures 210, 220. Although the first compensation zones 111 are not connected to each other, the base portion 120 between the first compensation zones 111 is completely depleted, and a predominant portion of the semiconductor portion 100 causes the conversion of incident radiation into electric current.
    Unlike superjunction insulated gate field effect transistor (IGFET) devices, radiation conversion devices are not operated in the forward or on state, so that the fact that the first compensation zones 111 are at least partially floating or electrically floating Function of the device is not adversely affected.
    The first compensation zones 111 may be formed by repeating a sequence comprising (i) growing semiconductor layers by epitaxy and (ii) introducing dopants into vertically aligned surfaces of portions of the vertically grown semiconductor layers, as well as a final anneal to control the diffusion of the implanted dopants. While structurally connected first compensation zones 111 require a sufficiently high number of epitaxial layers and / or a sufficiently long anneal to ensure that the first compensation zones 111 connect, the embodiments relying on unconnected first compensation zones 111 come with a lower number of epitaxial layers and / or a reduced annealing time, so that the fabrication of the radiation conversion device 910 is simplified and less expensive.
    The radiation conversion device 910 of FIG. 2D corresponds to the radiation conversion device of FIG. 2A, wherein the first dopant type is n-type and the second dopant type is p-type. In addition, the base portion 120 may include a p-type buffer layer 125 that receives an applied voltage. A dopant concentration in the buffer layer 125 may be lower than in portions of the base portion 120 outside the buffer layer 125. The buffer layer 125 may be epitaxially grown and in-situ doped during growth. Since radiation damage gradually increases the acceptor concentration, the embodiment eliminates a conduction type change in low-doped portions of the base portion 120 within the operating life.
    The radiation conversion device 910 of FIGS. 3A to 3C differs from the radiation conversion device 910 of FIG. 2A in that the first contact zones 118 directly adjoin the first compensation zones 111 closest to the main surface 101. In addition, the second compensation zones 122 are formed, at least in part, by introducing dopant of the second conductivity type into the surface of the epitaxial semiconductor layers, for example by masked or unmasked implantations. Vertical dopant profiles of the second compensation zones 122 correspond approximately to a Gaussian distribution. Forming a significant portion, for example 50% or more than 90%, of the dopants of the second compensation zones 122 by implantation processes, rather than in-situ doping during epitaxial growth, can increase the precision of the compensation.
    In the course of operation, as the radiation gradually generates more acceptor atoms and shifts the doping level in a lightly doped background portion 126 of the base portion 120 outside the n-type to p-type second compensation zones 122, the more heavily doped n-doped second ones Compensating zones 122 still ensure the complete depletion of the portions of the base portion 120 between adjacent column structures 110.
    FIG. 3B shows the electric field of the radiation conversion device 910 of FIG. 3A before aging, and FIG. 3C shows the electric field for the same device 910 after simulated aging, wherein the surface concentration of p-type dopant after aging is 2 × 1013 cm-2 assuming that this is significantly higher than p-type area concentrations achieved by regular aging processes.
    In addition, aging results in an electric field gradient which is advantageous in some respects. For example, a maximum field strength occurring at the edges of the columnar structures 110 is reduced. The effect can improve the radiation hardness of a termination structure in a peripheral portion of the radiation conversion device 910. In the case of p-type base epitaxy, aging can even be in an even more advantageous electrical. Field gradients result because the electric field strength gradually decreases along the interface of the columnar structures 110 of the base portion 120 and the maximum electric field appears to be amplified in a lateral layer portion of the base portion 120 parallel to and directly to the second contact regions 128.
    According to one embodiment, the n-type first compensation zones 111 can be provided by fast-diffusing donor-type dopants, for example sulfur S or selenium Se, so that the temperature / time budget of the diffusion process can be significantly reduced. In addition, donor materials such as sulfur S and selenium Se, which provide an energy state deep in the band gap of the silicon, increase the diffusion length in the detector volume as a result of the effectively reduced free carrier concentration.
    In Fig. 4A, the base portion 120 of the radiation conversion device 910 includes second compensation zones 122, the vertical dopant profiles being approximately Gaussian distributions. Two or more second pore-panning zones 122 are aligned along the vertical direction and form further pillar structures that are separated from the pillar structures 110. A uniformly doped background subregion 126 of the base subregion 120 can separate the column structures 110 with the first compensation zones 111 and the further column structures with the second compensation zones 122. The pillar structures 110 may be connected to first contact zones 118 and the further pillar structures may be connected to one or more second contact zones 128.
    The net dopant concentration in the second compensation zones 122 may substantially correspond to the dopant concentration in the corresponding first compensation zones 111. The remaining background portions 126 may be intrinsic, n-type or p-type. The base portion 120 may be completely depleted even at comparatively high dopant concentrations in the compensation zones 111, 122.
    The first compensation zones 111 of each pillar structure 110 may be separated from each other by the uniformly doped background portions 126 of the base portion 120, and the second compensation zones 122 of each further pillar structure may be separated by the uniformly doped background portion 126.
    According to the embodiment of Fig. 4B, the first compensation zones 111 of each pillar structure 110 are structurally interconnected or overlapping each other and the second compensation duties 122 of each further pillar structure are structurally connected or overlapped with each other.
    FIG. 4C relates to a radiation conversion device 910 that provides both first and second electrodes 210, 220 on the major surface 101. Non-transparent electrode materials may be used for both the first and second electrodes 210, 220, with the back surface 120 forming the radiation-receiving surface through which the radiation enters the semiconductor portion 100.
    FIGS. 5A and 5B relate to a radiation conversion device 910 having a semiconductor subregion 100, which comprises stratiform first compensation zones 111 of a first conductivity type arranged in column structures 110. The first compensation zones 111 of each pillar structure 110 may be connected to each other or may be separate from each other. Between adjacent pillar structures 110, second compensation zones 122 of a second, complementary conductivity type may form further pillar structures. Each pillar structure 110 extends in a vertical direction and in a first lateral direction with respect to a main surface 101 of the semiconductor portion 100. A first electrode structure 210 directly adjoins the semiconductor subregion 100 at the main surface 101 and comprises a multiplicity of stripes. Each strip is associated with at least two columnar structures 110. According to the illustrated embodiment, the strips directly adjoin first contact zones 118, wherein each of the first contact zones 118 is associated with two parallel columnar structures 110.
    According to the embodiment shown in FIG. 6, the strips of the first electrode 210 extend in a second lateral direction orthogonally intersecting the first lateral direction, wherein the first lateral direction is defined by the strip-shaped column structures 110. Heavily doped first contact zones 118 are parallel to the strips to provide Schottky contact between the first electrode structure 210 and the columnar structures 110.
    A first distance d1 of the strips of the first electrodes 210 is decoupled from a second distance d2 of the columnar structures 110. According to one embodiment, the second distance d2 of the pillar structures 110 is significantly smaller, for example at most half, than the first distance d1, in order to achieve both a high doping level in the detector area and a high spacing of the stripes of the first electrode structure 210, which makes the fabrication the radiation conversion device simplifies and makes more reliable.
    Figs. 7A to 7C relate to the production of a radiation conversion device. On a semiconductor base substrate 100a, a semiconductor layer 100b is epitaxially grown. The crystal lattice of the grown semiconductor layer 100b grows congruent to the crystal lattice in the base substrate 100a. A mask layer is deposited on the grown semiconductor layer 100b and patterned by a photolithographic process to obtain a dopant mask 310 with openings 315. The grown semiconductor layer 100b may be an intrinsic layer, a lightly p-doped or slightly n-doped layer. Dopants of a first conductivity type, for example p-type, are introduced through the openings 315 in the dopant mask 310 into the exposed first surface portions of the grown semiconductor layer 100b to form implantation zones 111a. The implantation energy is chosen so that the dopants are implanted in close proximity to the exposed surface of the grown semiconductor layer 100b.
    Fig. 7A shows the implantation zones 111a near the exposed surface of the grown semiconductor layer 100b in first portions exposed by the implantation mask 310. The implantation mask 310 is removed and a cycle of (i) growing a semiconductor layer by epitaxy and (ii) forming an implantation mask having openings aligned along the openings in the first implantation mask 310 (iii) implantation of dopants of the first conductivity type and (iv) removal the implantation mask is repeated several times.
    Fig. 7B shows a semiconductor subregion 100 obtained by successively growing five semiconductor layers 100b to 10Of by epitaxy on the base substrate 100a. In the first to fourth semiconductor layers 100b to 100e, implanted regions 111a to 111g are aligned along the vertical direction orthogonal to a main surface 101 of the obtained semiconductor portion 100. Annealing is performed so that the dopants of the implanted
    权利要求:
    Claims (20)
    [1]
    Out diffuse zones 111 a to 111 d to form first compensation zones 111 arranged in columnar structures 110. The annealing is terminated before the first compensation zones 111 overlap with each other. Then first contact zones 118 of the first conductivity type are formed which directly adjoin the main surface 101. Second contact zones 118 of the second conductivity type may be provided on the back surface 102. Electrode structures 210, 220 are provided to form Schottky contacts with the first and second contact zones 118, 128. Fig. 7C shows the resulting radiation conversion device 910 similar to the radiation conversion device of Fig. 2A. According to a further embodiment, each cycle may comprise an unmasked implantation of dopants of the second conductivity type before or after the masked implant of the dopants of the first conductivity type in order to obtain the radiation conversion device of FIG. 3A. FIGS. 8A to 8C relate to a further method that provides a second implantation mask 302 covering the implantation zones 111 of FIG. 7A. In each cycle, dopants of the second conductivity type complementary to the first conductivity type are implanted in the epitaxial semiconductor layer 100b to form further implanted zones 122a of the second conductivity type in some or all of the epitaxial semiconductor layers 100b to 100t. The sequence of implantations of the first and second conductivity types may be reversed for each semiconductor layer 100b to 10Of. Referring to Figure 9, a method of fabricating a radiation conversion device includes epitaxially growing a sequence of semiconductor layers on a semiconductor substrate (802), wherein dopants of a first conductivity type are in first portions of an exposed surface in each of the grown semiconductor layers prior to growing the subsequent one of the semiconductor layers be introduced (804). The grown semiconductor layers are annealed to form first compensation zones of the introduced dopants (806). The first compensation zones remain separated by a base portion, with second compensation zones of a second complementary conductivity type separating the first compensation zones in a lateral direction and further portions of the base portion separating the first compensation zones in a vertical direction. Although specific embodiments are illustrated and described herein, it will be understood by those skilled in the art that a variety of alternative and / or equivalent constructions may be used for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and their equivalents. claims
    A radiation conversion apparatus (910) comprising: a semiconductor portion (100) made of a single crystalline semiconductor material, said first compensation zones (11.1) of a first conductivity type, and a base portion (1.20) separating said first compensation zones (111), said first compensation zones (111) are arranged in pillar structures (110), each pillar structure (110) has at least two of the first compensation zones (111) and extends in a vertical direction with respect to a main surface (101) of the semiconductor portion (100), and the base portion (FIG. 120) between adjacent one of the columnar structures (1.10) has second compensation zones (122) of a second, complementary conductivity type, the columnar structures (110) being striped and extending in a first lateral direction with respect to the main surface (101).
    [2]
    The radiation conversion apparatus (910) according to claim 1, wherein portions (121) of the base portion (120) separating the first compensation zones (111) in the vertical direction have a uniform dopant distribution.
    [3]
    The radiation conversion apparatus (910) according to one of claims 1 and 2, wherein portions (121) of the base portion (120) separating the first compensation zones (111) in the vertical direction have a mean net dopant concentration of at most one twentieth of an average net dopant concentration in the first compensation zones (111),
    [4]
    The radiation conversion apparatus according to any one of claims 1 to 3, wherein portions (121) of the base portion (120) separating the first compensation zones (111) in the vertical direction have the second conductivity type.
    [5]
    The radiation conversion apparatus (910) according to any one of claims 1 to 4, wherein the second compensation zones (122) and the portions (121) of the base portion (120) separating the first compensation zones (111) in a vertical direction have a uniform dopant distribution and dopant profiles of the first compensation zones (111) along the vertical direction are approximately Gaussian distributions.
    [6]
    A radiation conversion apparatus (910) according to claim 1, further comprising: a first electrode structure (210) disposed in direct contact with the main surface (101),
    [7]
    The radiation conversion device (910) according to claim 6, wherein the first electrode structure (210) has a plurality of stripes extending in a second lateral direction intersecting the first lateral direction.
    [8]
    The radiation conversion device (910) according to claim 8, wherein the first electrode structure (210) has a plurality of stripes that are parallel to the first lateral direction.
    [9]
    A radiation conversion device (910) according to claim 8, wherein each of the strips is assigned to at least two of the column structures (110).
    [10]
    The radiation conversion device (910) according to any one of claims 6 to 9, wherein the semiconductor subregion (100) has a first contact region (118) of the first conductivity type, the first contact region (118) has an average net dopant concentration that makes ohmic contact with the first first electrode structure (210) and the first contact region (118) directly adjacent to a first compensation zones (111) of the associated columnar structures (110) and the first electrode structure (210).
    [11]
    The radiation conversion device (910) according to any one of claims 1 to 10, wherein the semiconductor subregion (100) comprises a second contact region (128) of the second conductivity type, the second contact region (128) has a mean net dopant concentration which makes an ohmic contact with one second electrode structure (220) and the second contact region (128) directly adjacent to the base portion (120) and the second electrode structure (220).
    [12]
    The radiation conversion device (910) according to claim 11, wherein the second contact region (128) is directly adjacent to the main surface (101).
    [13]
    The radiation conversion device (910) according to claim 11, wherein the second contact region (128) directly adjoins a surface (102) of the semiconductor subregion (100) opposite to the main surface (101).
    [14]
    14. A radiation conversion device (910) according to claim 1, wherein the strips extend in a second lateral direction intersecting the first lateral direction.
    [15]
    The radiation conversion device (910) of claim 1, wherein the strips are parallel to the first lateral direction and each strip extends between two adjacent ones of the column structures (110).
    [16]
    The radiation conversion apparatus (910) of claim 1, wherein the base portion (120) includes a background portion (126), the second compensation zones (122) form further column structures extending in the vertical direction, and vertical dopant profiles of the second compensation zones (122) are Gaussian Ver divisions are.
    [17]
    17. A radiation conversion device (910) according to claim 1, wherein each of the columnar structures (110) comprises at least two spatially separated first compensation zones (111).
    [18]
    A radiation conversion apparatus according to claim 1, wherein portions (121) of the base portion (120) separating the second compensation zones (111) in the vertical direction are of the first conductivity type.
    [19]
    19. A method of manufacturing a radiation conversion apparatus, comprising: epitaxially growing a sequence of semiconductor layers (100b-10Of) on a semiconductor substrate (100a); Introducing, in at least two of the semiconductor layers, dopants of a first conductivity type into exposed portions of a process surface of a preceding one of the semiconductor layers prior to growing a subsequent one of the semiconductor layers on the preceding one; and annealing the grown semiconductor layers (100b-100f) to form first compensation zones (111) from the introduced dopants, wherein annealing is terminated before the first compensation zones (111) structurally connect, annealing terminating before the first compensation zones settle structurally connect such that the first compensation zones are separated by a base portion, wherein second compensation zones of a second complementary type of conduct separate the first compensation zones in a lateral direction,
    [20]
    20. The method of claim 19, wherein further portions of the base portion separate the first compensation zones in a vertical direction.
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    同族专利:
    公开号 | 公开日
    JP6132805B2|2017-05-24|
    JP2014216651A|2014-11-17|
    US20140319641A1|2014-10-30|
    US8952478B2|2015-02-10|
    JP2016106407A|2016-06-16|
    CH707923A2|2014-10-31|
    JP6178437B2|2017-08-09|
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    法律状态:
    2018-01-31| NV| New agent|Representative=s name: E. BLUM AND CO. AG PATENT- UND MARKENANWAELTE , CH |
    优先权:
    申请号 | 申请日 | 专利标题
    US13/869,121|US8952478B2|2013-04-24|2013-04-24|Radiation conversion device and method of manufacturing a radiation conversion device|
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