• 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:
    PURPOSE: A formation method of ferroelectric capacitors contained a bismuth(Bi) is provided to prevent out-diffusion of Bi by forming Bi2-iO3-j film on upper and lower portions of a ferroelectric layers. CONSTITUTION: A lower electrode(9) is formed on a silicon substrate(S). A first Bi2-iO3-j (0 < i < 1, 0 < j < 1) layer(10) is formed on the lower electrode(9). A ferroelectric layer(11) contained Bi is formed on the Bi2-iO3-j layer(10). A second Bi2-iO3-j layer(12) is formed on the ferroelectric layer(11). An upper electrode(13) is formed on the second Bi2-iO3-j layer(12). The Bi2-iO3-j layers(10,12) are deposited by CVD, PVD or laser ablation deposition methods.
    公开号:KR20000027681A
    申请号:KR1019980045672
    申请日:1998-10-29
    公开日:2000-05-15
    发明作者:김남경
    申请人:김영환；현대전자산업 주식회사；
    IPC主号:
    专利说明:

    Capacitor Formation Method Having Ferroelectric Film Containing Bismuth
    BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of semiconductor device manufacturing, and more particularly, to a method of forming a ferroelectric capacitor capable of preventing Bi deficiency of a ferroelectric film containing Bi.
    Ferroelectric films such as SBTO (Sr x Bi 2-y Ta 2 O 9-z ) and SBTNO (Sr x Bi 2-y (Ta i Nb j ) 2 O 9-z ) are strontium-tantalum-oxide (Sr-Ta- In the perovskite structure of O), a bismuth-oxide (Bi 2-i O 3-j , where 0 <i <1, 0 <j <1) film is formed between layers. The fatigue resistance is improved by the consumption of oxygen, vacancy, and ions that cause fatigue by the Bi 2-i O 3-j interlayer film. Therefore, the Bi 2-i O 3-j film forming a layer structure in the SBTO and SBTNO ferroelectric films is an important factor for improving physical and electrical properties.
    Conventional ferroelectric capacitor formation process is made of the process shown in Table 1.
    step First step 2nd step 3rd step 4th step 5th step 6th step fair Bottom electrode formation SBTO application Bake Nuclear formation Grain growth Upper electrode formation
    In order to generate nuclei on SBTO and SBTNO perovskite, heat treatment is performed at a temperature of 750 ° C. for 30 seconds, followed by heat treatment for 1 hour in a furnace at 800 ° C. in an O 2 atmosphere to grow crystal grains from the nucleus. In this case, the grown grains have a size of 2000 mm 3 to 3000 mm 3. However, Bi 2-i O 3-j , which has a melting point of about 800 ° C, is highly volatilized in the 800 ° C furnace annealing process performed after nucleation, and Bi diffuses along the grain boundaries of the lower electrode, the upper electrode, and the interface. do. As a result, Bi is deficient in the ferroelectric film, thereby changing stoichiometry, thereby reducing the electrical properties of the thin film or creating an abnormal structure. When Bi diffuses or volatilizes more severely, it becomes a pyrocloro structure and exhibits a dielectric property having no polarization or a small value as an electrical property.
    As described above, it is expected that the stoichiometric ratio will be different from the initial chemical state due to the volatilization or diffusion of Bi in the heat treatment process, which is a grain growth process. However, this compensation is extremely small in the process window and is highly dependent on the process conditions, which brings a lot of process difficulties to maintain the stoichiometric ratio.
    The present invention devised to solve the above problems is to provide a method of forming a ferroelectric capacitor capable of preventing Bi deficiency of the Bi-containing ferroelectric film.
    1 to 5 are cross-sectional views of a ferroelectric capacitor forming process according to an embodiment of the present invention.
    * Explanation of reference numerals for the main parts of the drawings
    9: lower electrode 10: first Bi 2-i O 3-j film
    11: ferroelectric film 12: second Bi 2-i O 3-j film
    13: upper electrode
    The present invention for achieving the above object is a first step of forming a lower electrode; Forming a first Bi 2-i O 3-j (0 <i <1, 0 <j <1) film on the lower electrode; Forming a ferroelectric film containing Bi on the first Bi 2-i O 3-j film; Forming a second Bi 2-i O 3-j film on the ferroelectric film; And a fifth step of forming an upper electrode on the second Bi 2-i O 3-j film.
    In order to keep the stoichiometric ratio constant, Bi is diffused through upper and lower electrodes and grain boundaries by forming Bi 2-i O 3-j films having a predetermined thickness on top and bottom of a ferroelectric film containing Bi, such as SBTO and SBTNO. Or to prevent volatilization.
    Hereinafter, a method of forming a ferroelectric capacitor according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5.
    First, as shown in FIG. 1, the device isolation film 1, the gate oxide film 2, the gate electrode 3, the first interlayer insulating film 4, the bit line 5, the second interlayer insulating film 6 and poly The adhesive film 8 and the lower electrode 9 are sequentially formed on the silicon substrate S on which the silicon plug 7 is formed.
    In this case, the lower electrode is formed of a metal such as a Pt film, an Ir film, or a Ru film, or a conductive oxide such as IrO 2-x or RuO 2-y . When the lower electrode is formed of Pt, the adhesive film 8 forms a Ti film, a Ta film, a Ta 2 O 5 film, a Ta x O y film, or a Ru film. When the adhesive film is formed of Ti, the Ti film is oxidized. TiO x is formed on the polysilicon plug 7. In addition, when the adhesive film 8 and the lower electrode 9 are formed in a Ti / Pt stacked structure, an oxidation process is performed in a subsequent process so that the TiO 2-x material is formed at the interface.
    Next, as shown in FIG. 2, a first Bi 2-i O 3-j film 10 is formed on the lower electrode 9. In this case, the first Bi 2-i O 3-j film 10 is formed by chemical vapor deposition (CVD), physical vapor deposition (PVD), or laser ablation deposition. do. In which the bonding film Ti and the lower electrode Pt laminated structure of claim 1 Bi 2-i O 3- j for forming a film (10) 300 Å to 700 of Å thick Bi 2-i O 3-j film 500 ℃ to 750 It is formed at the deposition temperature of ℃.
    Next, as shown in FIG. 3, SBTO, SBTNO, or the like may be formed by spin-on, physical vapor deposition (PVD), organic chemical vapor deposition (CVD), or liquid source mixed chemical deposition (LSMCD). The ferroelectric film 11 containing Bi is formed.
    Next, as shown in FIG. 4, the amorphous second Bi 2-is deposited on the ferroelectric film 11 at 300 ° C. to 500 ° C. by an organic chemical vapor deposition (CVD), a physical vapor deposition (PVD), or a laser deposition deposition method. The i 0 3-j film 12 is formed. At this time, the reason for forming the amorphous second Bi 2-i O 3-j film 12 at low temperature is that volatilization or diffusion of Bi due to the formation of the second Bi 2-i O 3-j film 12 does not occur. This is to avoid.
    Next, as shown in FIG. 5, the upper electrode 13 is formed on the second Bi 2-i O 3-j film 12, and the upper electrode 13 and the second Bi 2-i O 3- are formed. The j film 12, the ferroelectric film 11, the first Bi 2-i O 3-j film 10, the lower electrode 9 and the adhesive film 8 are patterned to form a capacitor.
    Thereafter, an interlayer insulating film or the like such as a SiO 2 film is formed.
    In the present invention as described above, Bi 2-i O 3-j film is formed on the upper and lower portions of ferroelectric films such as SBTO and SBTNO containing Bi, so that Bi is diffused to the upper and lower electrodes when furnace anneal is performed. Volatilization can be prevented. Therefore, even if the furnace heat treatment process is completed, the stoichiometric ratio of the SBTO and SBTNO ferroelectric films can maintain the initial chemical state and can improve the resistance to fatigue even electrically.
    The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made in the art without departing from the technical spirit of the present invention. It will be apparent to those of ordinary knowledge.
    权利要求:
    Claims (4)
    [1" claim-type="Currently amended] In the method of forming a ferroelectric capacitor,
    Forming a lower electrode;
    Forming a first Bi 2-i O 3-j (0 <i <1, 0 <j <1) film on the lower electrode;
    Forming a ferroelectric film containing Bi on the first Bi 2-i O 3-j film;
    Forming a second Bi 2-i O 3-j film on the ferroelectric film; And
    A fifth step of forming an upper electrode on the second Bi 2-i O 3-j film
    Ferroelectric capacitor formation method comprising a.
    [2" claim-type="Currently amended] The method of claim 1,
    The first Bi 2-i O 3-j film and the second Bi 2-i O 3-j film are deposited by chemical vapor deposition (CVD), physical vapor deposition (PVD) or laser deposition. A method of forming a ferroelectric capacitor, which is formed by a laser ablation deposition method.
    [3" claim-type="Currently amended] The method according to claim 1 or 2,
    The ferroelectric layer is formed of SBTO (Sr x Bi 2-y Ta 2 O 9-z ) or SBTNO (Sr x Bi 2-y (Ta i Nb j ) 2 O 9-z ) .
    [4" claim-type="Currently amended] The method of claim 3, wherein
    In the fourth step,
    And forming the second Bi 2-i O 3-j film in an amorphous manner.
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    同族专利:
    公开号 | 公开日
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1998-10-29|Application filed by 김영환, 현대전자산업 주식회사
    1998-10-29|Priority to KR1019980045672A
    1998-10-29|Priority claimed from KR1019980045672A
    2000-05-15|Publication of KR20000027681A
    2002-05-09|Application granted
    2002-05-09|Publication of KR100321708B1
    优先权:
    申请号 | 申请日 | 专利标题
    KR1019980045672A|KR100321708B1|1998-10-29|Method for forming capacitor having ferroelectric layer in which bi contained|
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