• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    In the present invention, when forming a crystalline layer of a group III to V nitride compound semiconductor, the nitride compound semiconductor layer is first superimposed on a substrate to form a base layer, and a group III of formula In x Ga y Al z N Hydride gas phase epitaxy at group V-nitride compound semiconductors, where x, y and z are each independently a number from 0 to 1 and x + y + z is 1 at a growth pressure of at least 800 Torr. It grows epitaxially on a base material by the (HVPE) method. By setting the growth pressure to 800 Torr or more, the crystallinity of the group III to V nitride compound semiconductor can be remarkably improved, and the defect density thereof can be reduced.
    公开号:KR20030077435A
    申请号:KR20030018478
    申请日:2003-03-25
    公开日:2003-10-01
    发明作者:히라마쓰가즈마사；미야케히데토；보야마신야；마에다다카요시；이예치카야스시
    申请人:스미또모 가가꾸 고교 가부시끼가이샤；
    IPC主号:
    专利说明:

    Method of manufacturing III-V group compound semiconductors
    [7] The present invention relates to a method for manufacturing a group III to V nitride compound semiconductor by the hydride vapor phase epitaxy (HVPE) method.
    [8] Group III-V nitride compound semiconductors of the formula In x Ga y Al z N, where x, y and z are each independently a number from 0 to 1, and x + y + z is 1, a group III element By varying the content, the direct band gap energy can be adjusted. For this reason, since it can respond to the light energy of the wavelength of an ultraviolet-infrared light, they can be utilized as a material for high efficiency light emitting elements about the expansion range from an infrared ray to a visible light region. In addition, because they have a larger band gap than Si, GaAs, and other semiconductors that are widely used so far, they can maintain semiconductor properties up to high temperatures at which conventional semiconductors cannot operate. By using this property basically, an electronic device having excellent environmental resistance can be manufactured.
    [9] However, due to the very high vapor pressure of the group III to V nitride compound semiconductors near the melting point, the growth of large crystals is very difficult, and it is impossible to obtain crystals of practical size for use as a substrate for semiconductor chip manufacturing. Thus, in the manufacture of compound semiconductors, Si, GaAs, SiC, sapphire, ZrB 2 , or other materials having a crystal structure similar to that of compound semiconductors and capable of producing large crystals, are used as the substrate, It is common to epitaxially grow a crystalline thin film layer. At present, by using such a method, relatively good crystals of the compound semiconductor can be obtained. By using the organometallic vapor phase epitaxy (MOVPE) method to perform growth using a buffer layer, it is generally possible to achieve a half value width of about 200 seconds, as measured from the x-ray locking curve.
    [10] On the other hand, the hydride vapor phase epitaxy (HVPE) method is preferably compared with other methods for growing a compound semiconductor in that the growth rate and the performance and growth rate of achieving high purity crystal growth by suppressing impurity inflow are high. However, HVPE lags behind the MOVPE method and other methods in establishing heteroepitaxial methods by two-step growth using buffer layers. In fact, a thin film having a thickness of about 3 μm grown by MOVPE method or the like is used as the base layer, and the thick layer of the compound semiconductor is grown epitaxially on the base layer by the HVPE method. However, it is difficult to obtain high quality crystals over a wide area because cracks occur even when homoepitaxial growth is performed by the HVPE method. In addition, other drawbacks become apparent, such as the crystallinity of the growth layer being inferior to the substrate, as evidenced by the fact that the half-width of the x-ray locking curve (XRC) of the growth layer is wider than the substrate.
    [11] It is an object of the present invention to provide a method for obtaining high quality Group III-V compound semiconductor crystals.
    [12] Still another object of the present invention is to provide a method for growing a group III to V compound semiconductor crystal having excellent crystallinity by HVPE.
    [13] It is still another object of the present invention to provide a method for manufacturing a group III-V compound semiconductor capable of epitaxially growing a group III-V compound semiconductor having excellent crystallinity at low cost.
    [1] 1A-1D are process diagrams for explaining a method that is an aspect of the present invention.
    [2] FIG. 2 is a schematic diagram illustrating an essential part of a vapor growth semiconductor manufacturing system used to perform the process of FIGS. 1A-1D.
    [3] 3 is a graph showing the temperature profile in the reactor of the system shown in FIG.
    [4] 4 is a graph showing how the XRC half-width varies as a function of growth pressure in test specimens made in accordance with the present invention.
    [5] 5 is a micrograph showing the GaN thin film surface state of a test piece prepared according to the present invention.
    [6] FIG. 6 is a micrograph showing the GaN thin film surface state of a test piece manufactured by a conventional method. FIG.
    [14] The inventors have carried out a number of different tests and experiments in order to achieve the object of the present invention. These presuppose that the GaN crystal growth by HVPE method is generally performed at atmospheric pressure, but it can be expected that the change in growth pressure can affect the crystallinity. This approach leads to the discovery that the growth pressure is significantly improved when the pressure is slightly above atmospheric pressure. The present invention has been made based on this finding.
    [15] According to the present invention, the method for producing a group III to V nitride compound semiconductor by the HVPE method is characterized in that the growth pressure is set to 800 Torr or more. The growth pressure is preferably at least 850 Torr, more preferably at least 900 Torr. When the growth pressure is less than 800 Torr, the effects of the present invention cannot be obtained.
    [16] In accordance with another feature of the invention, a Group III-V nitride compound semiconductor of Formula In x Ga y Al z N wherein x, y and z are each independently a number from 0 to 1, and x + y + z is 1), the crystalline layer of the Group III to Group V compound semiconductor having excellent crystallinity is prepared by the hydride vapor phase epitaxy method, and the substrate is made of Group III to V under a growth pressure of 800 Torr or more. It can be obtained by forming a group nitride compound semiconductor on a substrate.
    [17] The substrate may be appropriately selected from materials such as Si, GaAs, SiC, ZrB 2 and sapphire. Moreover, the nitride compound semiconductor previously grown on one of the above-mentioned substrates by MOVPE method, molecular beam epitaxy (MBE) method, etc. can be used as a board | substrate. In the case where the Group III-V nitride compound semiconductors are epitaxially grown on the substrate using the HVPE method, the crystallinity of the obtained Group III-V nitride compound semiconductors is set to a slightly higher atmospheric pressure than the atmospheric pressure. It can be significantly improved compared to growth in. The reason for this is not clear, but by pressurization, the growth mechanism is considered to be changed in a manner that improves crystallinity. In addition, after the nitride-based compound semiconductor layer is first formed on the substrate, the necessary group III-V nitride compound semiconductor crystal layer is grown on the nitride-based compound semiconductor layer by hydride vapor phase epitaxy under a growth pressure of 800 Torr or more. Can be.
    [18] 1A-1D are process diagrams illustrating a method that is an aspect of the present invention. First, a sapphire substrate 1 of suitable size is produced by washing to remove oil and water (FIG. 1A). Washing can be performed using various known cleaning solutions.
    [19] The washed sapphire substrate 1 is then placed in a MOVPE reactor and the surface etch is performed at a high temperature of about 1000 ° C. Subsequently, the buffer layer 2 of, for example, AlN, GaN, AlGaN or SiC is grown at a temperature of about 500 ° C. (FIG. 1B). After the formation of the buffer layer 2, the temperature is returned to about 1000 DEG C, and a group III to V nitride compound semiconductor layer 3 is formed (FIG. 1C). The multilayered semiconductor crystal obtained in this manner is used as the base layer (B) in the present invention. The obtained base layer (B) is a group III to V nitride compound semiconductor of the formula In x Ga y Al z N, wherein x, y and z are each independently a number of 0 to 1, and x + y + z is 1) is epitaxially grown in an HVPE reactor. The compound semiconductor grown in this embodiment is GaN. As a result, a GaN thin film 4 is obtained (FIG. 1D). The epitaxial growth of the GaN thin film 4 on the base layer B may be performed under temperature conditions suitably selected from those known in the art, but the growth pressure should be at least 800 Torr. A growth pressure of 800 Torr or more, ie slightly higher than atmospheric pressure, is used to significantly improve the crystal quality of the GaN thin film 4 than that obtained at atmospheric pressure.
    [20] FIG. 2 is a schematic diagram illustrating an essential part of a vapor growth semiconductor manufacturing system 10 that is an example of an HVPE semiconductor manufacturing system that can be used to implement the method of the present invention.
    [21] The vapor growth semiconductor manufacturing system 10 is equipped with a reactor 12 through which a source gas is supplied through a material supply line 11 from a starting material supply system (not shown). A susceptor 17 is provided to the reactor 12 for placement and heating of the base layer B. The starting material supply line 11 is a first line 11A for supplying N 2 purging gas, a second line 11B for supplying NH 3 and carrier gas, and a third for supplying HCl and carrier gas. It consists of the line 11C. The carrier gas supplied to the second line 11B may be N 2 or H 2 alone, or a mixture of N 2 and H 2 . The carrier gas supplied to the third line 11C may also be N 2 or H 2 alone or a mixture of N 2 and H 2 .
    [22] The exhaust line 13 is connected to the exhaust port 12A of the reactor 12. The flow rate of the exhaust gas discharged through the exhaust line 13 is regulated by the flow control valve VL provided in the exhaust line 13. This regulates the pressure in the reactor 12. Therefore, the growth pressure of the reactor 12 can be adjusted to a desired value by adjusting the flow control valve VL.
    [23] The pressure in the reactor 12 is detected by the pressure sensor 14. The output from the pressure sensor 14 is sent to a pressure indicator 15 which can monitor the growth pressure in the reactor 12. In this aspect, the pressure sensor 14 is attached to the exhaust line 13 between the exhaust port 12A and the flow control valve VL to detect the pressure in the reactor 12.
    [24] An electric furnace 16 for heating the susceptor 17 is provided. The reactor 12 can be heated to the required growth temperature profile by supplying a heating current from the power source (not shown) to the electric furnace 16. 3 shows an example of a growth temperature profile in reactor 12.
    [25] In the vapor growth semiconductor manufacturing system 10 of the type described above, the raw material gas supplied to the reactor 12 through the starting material supply line 11 is disposed on the susceptor 17 heated by the electric furnace 16. It reacts on base layer B (not shown in FIG. 2), and vapor-grows a target GaN thin film on base layer B. FIG. The used gas is discharged to the outside through the exhaust port 12A and sent to the exhaust gas treating apparatus (not shown) through the exhaust line 13.
    [26] The process is explained in more detail. The base layer B obtained in the process of FIG. 1C is disposed on the susceptor 17 in the reactor 12, the raw material gas is supplied to the reactor 12, and the growth temperature as shown in FIG. 3, for example. The profile is used to grow the GaN thin film 4 in the base layer B (see FIG. 1D).
    [27] Looking at the pressure display device 15, the operator adjusts the flow control valve VL to adjust the flow rate of the exhaust gas passing through the exhaust line 13, thereby regulating the growth pressure in the reactor 12, for example. For example, the flow rate of the raw material gas is set to be maintained at 800 Torr.
    [28] As described with reference to FIG. 1D, by maintaining the growth pressure slightly above atmospheric pressure, that is, 800 Torr or more, the high quality GaN thin film 4 is grown on the base layer B. FIG. In the case where the III-V nitride compound semiconductor is epitaxially grown by the HVPE method, the III-V nitride compound semiconductor having excellent crystallinity can be produced by only setting the growth pressure slightly higher than atmospheric pressure. . Accordingly, the present invention provides a method of excellent industrial value due to its ability to produce high quality Group III-V compound semiconductors at low cost.
    [29] The aspect of the present invention described above relates to the case where the GaN thin film 4 is grown on the base layer B. FIG. However, the present invention is not limited to this embodiment, and for example, when applied to regrow the GaN layer by ELO (epitaxial layer overgrowth), it can provide the same excellent effect. The present invention can also be directly applied when a substrate of a material whose lattice constant is relatively close to the lattice constant of the compound semiconductor to be manufactured is used as a base layer.
    [30] EXAMPLE
    [31] (Example 1)
    [32] The vapor-grown semiconductor manufacturing system 10 shown in FIG. 2 is undertaken as follows to grow a GaN thin film epitaxially on a GaN base layer formed on a sapphire substrate by the MOVPE method.
    [33] The temperature of the reactor 12 is controlled by adjusting the flow rate control valve VL at the same time as the start of the temperature rise, and the temperature profile in the reactor 12 is set as shown in FIG. 3. The starting material is fed at a constant V / III ratio, 25 (NH 3 partial pressure: 0.2 atm, GaCl partial pressure: 8 × 10 −3 atm) and grown by adjusting the internal pressure of the reactor 12 to 910 Torr. Since the flow rate is constant, the carrier gas flow rate changes with pressure. Experiment with a mixed carrier gas consisting of equal amounts of N 2 and H 2 (N 2 : H 2 = 1: 1). Comparative test pieces are prepared at a pressure of 300 Torr and 760 Torr.
    [34] The test specimens of the present invention prepared at the growth pressure of 910 Torr and the comparative specimens prepared at the growth pressures of 300 Torr and 760 Torr were evaluated for crystallinity by X-ray diffraction analysis. The rate of change in the half width of the XRC (x-ray locking curve) for (0004) and (10-10) obtained by analysis is plotted as a function of growth pressure in FIG. 4. In the (0004) and (10-10) diffraction results, the half width (FWHM: full width at the maximum half value) is the smallest when the growth pressure is 910 Torr, and the crystallinity is remarkable compared to the test pieces obtained at the growth pressures of 300 Torr and 760 Torr. It is evaluated to be improved. From these results, it can be seen that when the growth pressure is increased, the crystallinity of the GaN thin film is improved.
    [35] 5 shows the surface state of a GaN thin film grown at a growth pressure of 910 Torr. 6 shows the surface state of a GaN thin film grown at a normal growth pressure of 760 Torr. Observation of both surfaces confirms that the increase in growth pressure from 760 Torr to 910 Torr can suppress cracking and yield a remarkably good surface condition.
    [36] (Example 2)
    [37] A test piece is prepared by growing a GaN thin film on a GaN base layer formed on a sapphire substrate by the MOVPE method. Except for changing the growth pressure to 836 Torr, the same method as in Example 1 was used. The surface shape of the test piece is observed under an optical microscope. The surface was found to be crack free and of good quality as in Example 1. The half widths of the (0004) and (10-10) diffractions were found to be 175 seconds and 220 seconds, indicating that the crystallinity was excellent as in Example 1.
    [38] As described above, in the present invention, when the group III to V nitride compound semiconductor is epitaxially grown by the HVPE method, the group III to V nitride compound having excellent crystallinity is set by setting the growth pressure slightly higher than atmospheric pressure. A semiconductor can be manufactured simply. Accordingly, the present invention provides a method of excellent industrial value due to its ability to produce high quality Group III-V compound semiconductors at low cost.
    权利要求:
    Claims (5)
    [1" claim-type="Currently amended] Group III to V nitride compound semiconductors of the formula In x Ga y Al z N wherein x, y and z are each independently a number from 0 to 1, and x + y + z is 1 And forming by group hydride vapor phase epitaxy (HVPE) method with a growth pressure of 800 Torr or more while the group III to V nitride compound semiconductors are formed. .
    [2" claim-type="Currently amended] The method for producing a group III-V compound semiconductor according to claim 1, wherein a substrate is produced, and a group III-V nitride compound semiconductor is formed on the substrate.
    [3" claim-type="Currently amended] The method of claim 2, wherein the substrate is made of one material selected from Si, GaAs, SiC, ZrB 2, and sapphire.
    [4" claim-type="Currently amended] 3. The method of claim 2, wherein the nitride compound semiconductor layer is first superimposed on the substrate to form a base layer, and the group III to V nitride compound semiconductor are formed on the base layer.
    [5" claim-type="Currently amended] 5. The method of claim 4, wherein the nitride compound semiconductor layer is formed on the substrate by MOVPE or MBE.
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    同族专利:
    公开号 | 公开日
    US20030211710A1|2003-11-13|
    CN1447388A|2003-10-08|
    CN1310286C|2007-04-11|
    SG114605A1|2005-09-28|
    TW200403865A|2004-03-01|
    JP2004006568A|2004-01-08|
    US6946308B2|2005-09-20|
    DE10313315A1|2003-10-09|
    TWI254465B|2006-05-01|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2002-03-26|Priority to JPJP-P-2002-00084851
    2002-03-26|Priority to JP2002084851
    2002-07-19|Priority to JP2002211603A
    2002-07-19|Priority to JPJP-P-2002-00211603
    2003-03-25|Application filed by 스미또모 가가꾸 고교 가부시끼가이샤
    2003-10-01|Publication of KR20030077435A
    优先权:
    申请号 | 申请日 | 专利标题
    JPJP-P-2002-00084851|2002-03-26|
    JP2002084851|2002-03-26|
    JP2002211603A|JP2004006568A|2002-03-26|2002-07-19|Manufacture of 3-5 group compound semiconductor|
    JPJP-P-2002-00211603|2002-07-19|
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