Study on high growth-rate deposition of nanocrystalline silicon thin film with VHF-PECVD

Abstract

Abstract: Using the self-consistent one dimensional fluid model, equations of particle-balance, momentum, charged particle flux and current continuum have been established to study the behavior of chief particles in low-pressure very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD). The influence of VHF (very high frequency) has been analyzed and the profiles of SiH₃^-negative, electrons, SiH₃⁺positive density have been obtained. The simulation results show that the density of SiH₃^-negative changes with frequency and consequently the frequency controls the particle nucleation and growth; meanwhile, the densities of electron, SiH₃⁺positive and the electric field intensity also vary with frequency, so that the chemical reaction and the nanoparticle deposition are accelerated.

Key words: Low atmospheric-pressure discharge, Silane, Dust, Nanocrystalline silicon

摘要： 建立一维自洽流体模型，对低压甚高频等离子体放电中产生的主要粒子建立连续性方程、动量方程和电流平衡方程。分析了甚高频对纳米粒子的种子离子SiH₃^-及电子和正离子SiH₃⁺的影响，给出了种子离子、电子以及正离子密度随频率变化的时空演化过程。结果表明改变频率可以改变SiH₃^-的密度，从而控制粒子的成核及生长。同时甚高频放电也改变了等离子体中电子和正离子密度以及电场的强度，从而加快等离子体中的化学反应速度和纳米粒子的沉积速度。

关键词: 低气压放电, 硅烷, 尘埃, 纳米硅

CLC Number:

O539

ZHUANG Juan, WANG De-Zhen, GAO Xin-xin, WANG Yan-hui. Study on high growth-rate deposition of nanocrystalline silicon thin film with VHF-PECVD[J]. NUCLEAR FUSION AND PLASMA PHYSICS, 2009, 29(1): 87-91.

庄娟, 王德真, 高欣欣, 王艳辉. 甚高频放电加速纳米硅薄膜沉积速度的机理研究[J]. 核聚变与等离子体物理, 2009, 29(1): 87-91.

References

[1] Roth R M, Spears K G, Stein G D, et al. Spatial dependence of particle light scattering in an rf silane discharge [J]. Appl. phys. Lett., 1985, 46: 253-255.

[2] Jellum G M, Graves D B. Particulates in aluminum sputtering discharges [J]. J. Appl. Phys., 1990, 67: 6490- 6496.

[3] Hua J J, Ye M F , Wang L, et al. Pattern formation in a dusty plasma system [J]. Plasma Sci. Techn., 2004, 6: 2571-2575.

[4] Maemura Y, Yang S C, Fujiyama H. Transport of negatively charged particles by E×B drift in silane plasmas [J]. Surface and Coatings Techn., 1998, 98: 1351-1358.

[5] Tazoe K, Yang S C , Maemura Y, et al. Correlation betw- een silicon particles and modulated crossed magnetic field in silane plasmas [J]. Thin Solid Films, 1999, 341: 55-58.

[6] 佟嵩, 刘湘娜, 王路春, 等. PECVD 纳米晶粒硅薄膜的可见电致发光 [J]. 物理学报, 1997, 46: 1217-1222.

[7] 刘湘娜, 吴晓微, 鲍希茂, 等. 用等离子体增强化学汽相沉积方法制备纳米晶粒硅薄膜光致发光 [J]. 物理学报, 1994, 43: 965-990.

[8] Furukawa S, Tatsuro Miyasato. Quantum size effects on the optical band gap of microcrystalline Si:H [J]. Phys. Rev. B, 1988, 38: 5726-5729.

[9] Rucksckloss M, Landkammer B, Veprrek S. Light emit- ing nanocrystalline silicon prepared by dry processing: the effect of crystallite size [J]. Appl. Phys. Lett., 1993, 63: 1474-1476.

[10] Zhao X, Schoenfeld Olaf, Yoshinobu Aoyagi, et al. Violet luminescence from anodized microcrystalline silicon [J]. Appl. Phys. Lett., 1994, 65: 1290-1292.

[11] Takagi H, Ogawa H, Yamazaki Y, et al. Quantum size effects on photoluminescence in ultrafine Si particles [J]. Appl. Phys. Lett., 1990, 56: 2379-2380.

[12] Graf U, Meier J, Kroll U, et al. High rate growth of mic- rocrystalline silicon by VHF-GD at high pressure [J]. Thin Solid Film, 2003, 427: 37-40.

[13] Nandini Gupta, Stoffels W W , Kroesen G M W. Numeri- cal simulation of primary cluster formation in silane plasmas [J]. J. Phys. D: Appl. Phys., 2003, 36 : 837-841.

[14] Gallagher Alan. Model of particle growth in silane disch- arges [J]. Phys. Rev. E, 2000, 62: 2690-2706.

[15] Courteille C, Hollenstein Ch, Dorier J L, et al. Particle agglomeration study in rf silane plasmas: In situ study by polarization-sensitive laser light scattering [J]. J. Appl. Phys., 1996, 80: 2069-2078.

[16] Fridman A A, Boufendi L, Hbid T, et al. Dusty plasma formation: physics and critical phenomena . Theoretical approach [J]. J. Appl. Phys., 1996, 79: 1303-1314.

[17] Kortshagen U , Bhandarkar U. Modeling of particulate coagulation in low pressure plasmas [J]. Phys. Rev. E, 1999, 60: 887-898.

[18] Denysenko I B, Ostrikov K, Xu S, et al. Nanopowder management and control of plasma parameters in electronegative SiH4 plasmas [J]. J. Appl. Phys., 2003, 94: 6097-6107.

[19] Kathleen De Bleecker, Annemie Bogaerts, Renaat Gijbes. Numerical investigation of particle formation mechan- isms in silane discharges [J]. Phys. Rev. E, 2004, 69 (056409): 1-16.

[20] Kondo Michio, Fukawa Makoto, Guo Lihui. High rate growth of microcrystalline silicon at low temperatures [J]. J. Non-Crystalline Solids, 2000, 266: 84-89.

[21] Mai Y, Klein S, Carius R, et al. Microcrystalline silicon solar cells deposited at high rates [J]. J. Appl. Phys., 2005, 97(114913): 1-12.

[22] Boufendi A Bouchoule. Industrial developments of scien- tific insights in dusty plasmas [J]. Plasma Sources Sci. Techn., 2002, 11: A211-A218.

[23] Lieberman M A, Lichtenberg A J. Principles of plasma discharges and materials processing [M]. New York: Wiley, 1994.

[24] Ostrkov K, Denysenko I B, Vladimirov S V, et al. Low- pressure diffusion equilibrium of electronegative com- plex plasmas [J]. Phys. Rev. E, 2003, 67(056408): 1-13.

[25] Boeuf J P, Belenguer Ph. Transition from a capacitive to a resistive regime in a silane radio frequency discharge and its possible relation to powder formation [J]. J. Appl. Phys., 1992, 71: 4751-4754.

[26] 韩伟强. 纳米硅系薄膜研究 [D]. 浙江大学, 1995.

[27] Haaland P. Dissociative attachment in silane [J]. J. Chem. Phys., 1990, 93: 4066-4072.