红外LED用GaAs单晶的垂直梯度凝固制备研究

摘要/Abstract

摘要： GaAs单晶是当前光电子器件的主要衬底材料之一,在红外LED中有着重要应用。但杂质浓度高、迁移率低等缺点会严重影响红外LED器件性能。为生产出低杂质浓度、高迁移率、载流子分布均匀、高利用率的红外LED用掺硅垂直梯度凝固(VGF)法GaAs单晶,本文研究了热场分布、合成舟和炉膛材质、工艺参数对单晶的成晶质量、杂质浓度、迁移率、载流子分布的影响。利用CGSim软件对单晶生长热场系统进行数值模拟研究,温区一至温区六长度比例为8∶12∶9∶5∶5∶7时,恒温区达到最长,位错密度达到1 000 cm^-2以下,成晶率达到85%。采用打毛石英合成舟进行GaAs合成,用莫来石炉膛替代石英炉膛,可以获得迁移率整体高于3 000 cm²/(V·s)的GaAs单晶,满足红外LED使用要求。对单晶生长工艺参数展开研究,采用提高头部生长速度、降低尾部生长速度的方式提高单晶轴向载流子浓度均匀性,头尾部载流子浓度差降低33%,尾部迁移率从2 900 cm²/(V·s)提高到3 560 cm²/(V·s)。单晶有效利用长度提高33%,单晶利用率达到75%,大幅降低了原料损耗成本。

关键词: 砷化镓, 垂直梯度凝固, 位错密度, 载流子, 迁移率, 热场, 炉膛

Abstract: GaAs single crystal is one of the main substrate materials for optoelectronic devices, and has important applications in infrared LED. However, its high impurity concentration and low carrier mobility seriously restrict the performance of infrared LED devices. To obtain silicon doped GaAs single crystals prepared by vertical gradient freeze (VGF) method with low impurity concentration, high mobility, uniform carrier distribution and high utilization ratio, the influences of thermal field distribution, materials of synthetic boat and furnace, and process parameters on crystal quality, impurity concentration, mobility and carrier distribution of single crystal were studied in this paper. CGSim software was used to conduct numerical simulation research on the thermal field system of single crystal growth thermal field. When the length ratio from temperature zone 1 to temperature zone 6 is 8∶12∶9∶5∶5∶7, the constant temperature zone reaches the longest, the dislocation density is below 1 000 cm^-2, and the crystallization rate reaches 85%. With GaAs polycrystalline synthesized by roughening quartz synthesis boat, and the mullite furnace replacing the quartz furnace, GaAs single crystals with overall mobility higher than 3 000 cm²/(V·s) were obtained. The process parameters of single crystal growth were studied. The axial carrier concentration uniformity of single crystal is improved by increasing the head pulling speed and decreasing the tail pulling speed, by which the carrier concentration difference between the head and tail is reduced by 33%, and the tail mobility increase from 2 900 cm²/(V·s) to 3 560 cm²/(V·s). The effective utilization length of single crystal gains increase by 33%, and the utilization rate of single crystal reaches 75%, which greatly reduces the raw material consumption cost.

Key words: gallium arsenide, vertical gradient freeze, dislocation density, carrier, migration rate, hot field, furnace

中图分类号:

TN304.2

路淑娟, 陈蓓曦, 张路, 曹波, 张云博, 马志永, 齐兴旺, 于洪国. 红外LED用GaAs单晶的垂直梯度凝固制备研究[J]. 人工晶体学报, 2023, 52(2): 235-243.

LU Shujuan, CHEN Beixi, ZHANG Lu, CAO Bo, ZHANG Yunbo, MA Zhiyong, QI Xingwang, YU Hongguo. Prepration of GaAs Single Crystal for Infrared LED by Vertical Gradient Freeze Technology[J]. JOURNAL OF SYNTHETIC CRYSTALS, 2023, 52(2): 235-243.

参考文献

[1] 马英俊, 林泉, 于洪国, 等. 红外LED用掺硅HB-GaAs单晶纵向载流子浓度分布研究[J]. 人工晶体学报, 2020, 49(8): 1555-1561.
MA Y J, LIN Q, YU H G, et al. Concentration distribution of longitudinal carriers in silicon-doped HB-GaAs single crystals for infrared LED[J]. Journal of Synthetic Crystals, 2020, 49(8): 1555-1561(in Chinese).
[2] HABCHI M M, BEDOUI M, TOUNSI N, et al. Optical properties study of In_xGa_1-xAs/GaAs structures using spectral reflectance, photoreflectance and near-infrared photoluminescence[J]. Superlattices and Microstructures, 2014, 73: 71-81.
[3] BIANKA S, MARTIN B. Biometric protection for mobile devices is now more reliable: research award for the development of an infrared LED for reliable iris recognition in smartphones and tablets[J]. Optik & Photonik, 2016, 11(1): 16-19.
[4] 兰天平. B₂O₃质量对VGF晶体生长工艺成晶率的影响[J]. 天津科技, 2020, 47(2): 25-27.
LAN T P. Effect of B₂O₃ mass on crystallization rate of VGF crystal growth process[J]. Tianjin Science ＆ Technology, 2020, 47(2): 25-27(in Chinese).
[5] 王义. 硼扩散源及其在半导体器件中的应用[J]. 微电子学, 1977, 7(2): 44-50.
WANG Y. Boron diffusion source and its application in semiconductor devices[J]. Microelectronics, 1977, 7(2): 44-50(in Chinese).
[6] 高欢欢, 黎建明, 冯德伸, 等. ＜100＞P型4英寸无位错锗单晶的研制[J]. 稀有金属, 2018, 42(3): 285-290.
GAO H H, LI J M, FENG D S, et al. Development of 4-inch P-type dislocation-free germanium crystal with crystallographic orientation[J]. Chinese Journal of Rare Metals, 2018, 42(3): 285-290(in Chinese).
[7] CHARNIY L A, MOROZOV A N, BUBLIK V T, et al. Study of microdefects and their distribution in dislocation-free Si-doped HB GaAs by X-ray diffuse scattering on triple-crystal diffractometer[J]. Journal of Crystal Growth, 1992, 118(1/2): 163-175.
[8] 边义午. 3英寸VGF法GaAs单晶生长过程中固液界面的研究[D]. 北京: 北京有色金属研究总院, 2017.
BIAN Y W. Study on solid-liquid interface during VGF growth process of 3 inch GaAs single crystal[D]. Beijing: Beijing General Institute of Nonferrous Metals Research, 2017(in Chinese).
[9] 邓志杰, 郑安生. 半导体材料[M]. 北京: 化学工业出版社, 2004.
DENG Z J, ZHENG A S. Semiconductor materials[M]. Beijing: Chemical Industry Press, 2004(in Chinese).
[10] RUDOLPH P. Scaling of dislocation cells in GaAs crystals by global numeric simulation and their restraint by in situ control of stoichiometry[J]. Materials Science and Engineering: A, 2005, 400/401: 170-174.
[11] PODKOPAEV O I, ARTEMYEV V V, SMIRNOV A D, et al. Multiphysical simulation analysis of the dislocation structure in germanium single crystals[J]. Technical Physics, 2016, 61(9): 1286-1291.
[12] 金敏, 徐家跃, 谈惠祖, 等. 水平定向凝固法合成砷化镓多晶[J]. 上海应用技术学院学报(自然科学版), 2014, 14(3): 187-190.
JIN M, XU J Y, TAN H Z, et al. Synthesis of GaAs polycrystalline by horizontal directional solidification method[J]. Journal of Shanghai Institute of Technology (Natural Science), 2014, 14(3): 187-190(in Chinese).
[13] 徐学敏, 李希云, 崔仙航. 采用双层石英管道减少工艺中的沾污[J]. 半导体技术, 1983, 8(4): 47-48.
XU X M, LI X Y, CUI X H. Double-layer quartz pipe is used to reduce the contamination in the process[J]. Semiconductor Technology, 1983, 8(4): 47-48(in Chinese).
[14] 金太权. 测定石英玻璃的导热系数[J]. 吉林工学院学报, 1991, 12(1): 39-42.
JIN T Q. The precise determination of quartz thermal conductivity[J]. Journal of Changchun University of Technology, 1991, 12(1): 39-42(in Chinese).
[15] 赵鹏达, 赵惠忠, 张德强, 等. 莫来石轻质球形料结构与性能[J]. 人工晶体学报, 2017, 46(11): 2154-2158.
ZHAO P D, ZHAO H Z, ZHANG D Q, et al. Structure and properties of lightweight spherical mullite[J]. Journal of Synthetic Crystals, 2017, 46(11): 2154-2158(in Chinese).
[16] BAEUMLER M, BÖRNER F, KRETZER U, et al. Spatial variations of carrier and defect concentration in VGF GaAs∶Si[J]. Journal of Materials Science: Materials in Electronics, 2008, 19(1): 165-170.
[17] 林泉, 马英俊,于洪国, 等. 掺硫LEC-GaP单晶载流子的分布[J]. 河北大学学报(自然科学版), 2019, 39(4): 347-352.
LIN Q, MA Y J, YU H G, et al. Carrier concentration distribution in S-doped LEC-GaP single crystal[J]. Journal of Hebei University (Natural Science Edition), 2019, 39(4): 347-352(in Chinese).
[18] 张廷慧. 工艺参数对直拉掺锑锗单晶电阻率轴向均匀性的影响[D]. 北京: 北京有色金属研究总院, 2018.
ZHANG T H. Effect of technical parameter on axial resistivity uniformity of czochralski germanium single crystal[D]. Beijing: Beijing General Institute of Nonferrous Metals Research, 2018(in Chinese).