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采用化学气相沉积法进行6英寸(1英寸=2.54 cm)厚层4H-SiC同质外延片的快速生长，通过对工艺中预刻蚀、碳硅比(C/Si)和温度等关键参数优化，有效降低了厚层外延片表面缺陷密度。同时，采用傅里叶变换红外法、汞探针电容电压法和表面缺陷测试仪对厚层4H-SiC同质外延片各项参数进行表征。结果表明，生长的厚150μm外延层表面缺陷(三角形、掉落物以及掉落物引起的三角形)密度可降低至0.5 cm-2。外延片厚度均匀性为0.66%,外延层氮(N)掺杂浓度为2×1014 cm-3,N掺杂浓度均匀性为1.97%。此外，通过生长前对系统进行烘烤处理有效降低了反应腔系统的背景浓度，连续生长10炉次低掺杂浓度外延片，片间N掺杂浓度均匀性为4.56%,大大提高了炉次间的掺杂浓度均匀性。通过对工艺参数进行优化及外延前烘烤系统的方式，成功制备了150 mm高质量15 kV器件用4H-SiC同质外延片。
Abstract：The fast growth of 6-inch(1 inch=2.54 cm) thick 4 H-SiC homoepitaxial wafers was carried out by chemical vapor deposition method. The key parameters such as pre-etching, carbon to silicon ratio(C/Si) and temperature were optimized to effectively reduce the density of surface defects of the thick epitaxial wafers. Meanwhile, Fourier transform infrared method, mercury probe capacitance voltage method and surface defect tester were used to characterize various parameters of the thick layer 4 H-SiC homoepitaxial wafers. The results show that the density of surface defects(triangles, falling objects, and triangles caused by falling objects) of the grown epitaxial layer with a thickness of 150 μm can reduce to 0.5 cm-2. The thickness uniformity of the epitaxial wafer is 0.66%, the nitrogen(N) doping concentration of the epitaxial layer is 2×1014 cm-3, and the N doping concentration uniformity is 1.97%. In addition, by baking the system before growth, the background concentration of the reaction chamber system was effectively reduced. The low doping concentration epitaxial wafers were grown continuously for 10 runs. The uniformity of the N doping concentration between the wafers is 4.56%, which greatly improves the doping concentration uniformity of different runs. By optimizing the process parameters and the method of pre-epitaxially baking the system, 150 mm high-quality 4 H-SiC homoepitaxial wafers for 15 kV devices were successfully prepared.
[1] LA V L,CAMARDA M,LA M A.Mechanisms of growth and defect properties of epitaxial SiC[J].Applied Physics Review,2014,1(3):031301-1-031301-35.
[2] MIYAZAWA T,NAKAYAMA K,TANAKA A,et al.Epitaxial growth and characterization of thick multi-layer 4H-SiC for very high-voltage insulated gate bipolar transistors [J].Journal of Applied Physics,2015,118(8):085702-1-085702-10.
[3] HUANG A Q,ZHU Q,WANG L,et al.15 kV SiC MOSFET:an enabling technology for medium voltage solid state transformers [J].CPSS Transactions on Power Electronics and Applications,2017,2(2):118-130.
[4] SUN Y,FENG G,LI Z,et al.50 μm-thick 100 mm 4H-SiC epitaxial layer growth by warm-wall planetary reactor [J].Materials Science Forum,2014,778/779/780:163-166.
[5] MIYAZAWA T,NAKAYAMA K,TANAKA A,et al.Epitaxial growth and characterization of thick multi-layer 4H-SiC for very high-voltage insulated gate bipolar transistors [J].Journal of Applied Physics,2015,118(8):085702-1-085702-10.
[6] FUJIWARA H,KATSUNO T,ISHIKAWA T,et al.Impact of surface morphology above threading dislocations on leakage current in 4H-SiC diodes [J].Applied Physics Letters,2012,101(4):911-916.
[7] DAS H,SUNKARI S,JUSTICE J,et al.Statistical analysis of killer and non-killer defects in SiC and the impacts to device performance [J].Materials Science Forum,2020,1004:458-463.
[8] YAZDANFAR M,IVANOV I G,PEDERSED H,et al.Reduction of structural defects in thick 4H-SiC epitaxial layers grown on 4° off-axis substrates [J].Journal of Applied Physics,2013,113:223502-1-223502-8.
[9] 薛宏伟，袁肇耿，吴会旺.高质量 6 英寸4H-SiC 同质外延层快速生长 [J].微纳电子技术，2021,58(5):446-450.
[10] NIU Y X,TANG X Y,JIA R X,et al.Influence of triangle structure defect on the carrier lifetime of the 4H-SiC ultra-thick epilayer [J].Chinese Physics Letters,2018,35 (7):077103-1-077103-4.
[11] YANG J W,SONG H P,JIAN J K,et al.Characterization of morphological defects related to micropipes in 4H-SiC thick homoepitaxial layers [J].Journal of Crystal Growth,2021,568/569:126182-1-126182-6.
[12] ZHOU W L,PIROUZ P,POWELL J A.The origin of triangular surface defects in 4H-SiC CVD epilayers [J].Materials Science Forum,1998,264/265/267/268:417-420.
[13] ZHAO L X,YANG L,WU H W.High quality 4H-SiC homo epitaxial wafer using the optimal C/Si ratio [J].Journal of Crystal Growth,2020,530:125302-1-125302-4.
基本信息:
DOI：10.13250/j.cnki.wndz.2022.05.015
中图分类号:TN304
引用信息:
[1]吴会旺,杨龙,薛宏伟等.150mm高质量15kV器件用4H-SiC同质外延生长[J].微纳电子技术,2022,59(05):489-493.DOI:10.13250/j.cnki.wndz.2022.05.015.
基金信息:
工业和信息化部2020年产业基础再造和制造业高质量发展专项