6英寸半绝缘GaAs单晶VGF和VB联合生长技术  

Technology of 6-inch Semi-Insulating GaAs Single Crystals Grown by VGF and VB Method

作　　者：周春锋[1] 兰天平[1] 边义午 曹志颖[1] 罗惠英 Zhou Chunfeng;Lan Tianping;Bian Yiwu;Cao Zhiying;Luo Huiying(The 46th Research Institute,CETC,Tianjin 300220,China)

机构地区：[1]中国电子科技集团公司第四十六研究所,天津300220

出　　处：《半导体技术》2020年第5期383-389,共7页Semiconductor Technology

摘　　要：为了生长6英寸(1英寸=2.54 cm)半绝缘GaAs单晶,采用水平梯度凝固(HGF)法合成GaAs多晶。将装有籽晶、GaAs多晶、氧化硼和碳粉的热解氮化硼(PBN)坩埚装入石英管内并抽真空后密封。然后将石英管装入单晶炉内,升温熔化多晶并熔接籽晶后,采用垂直梯度凝固(VGF)法生长晶体肩部,采用垂直布里奇曼(VB)法生长晶体等径部分。在对VGF和VB晶体生长法进行理论分析的基础上,采取优化支撑结构、增加VGF晶体生长降温速率、优化VB晶体生长速度等措施提高6英寸GaAs晶体生长的成晶率至48%以上。基于半绝缘GaAs补偿理论,采取过量碳粉掺杂和El2的控制等措施,提高晶体电阻率至大于4×10^7Ω·cm,降低电阻率不均匀性至小于25%。通过优化生长界面,使GaAs单晶的位错密度降低至小于104 cm^-2。In order to grow the 6-inch(1 inch=2.54 cm) semi-insulating GaAs single crystal, the GaAs polycrystal was synthesized by the horizontal gradient freeze(HGF) method. The pyrolytic boron nitride(PBN) crucible containing the seed crystal, GaAs polycrystal, boron oxide and carbon powder was put into the quartz tube which would be vacuumed and sealed. Then the quartz tube was put into the single crystal furnace. After heating and melting polycrystal and welding the seed crystal, the shoulder part of crystal was grown by the vertical gradient freeze(VGF) method, and the equal diameter part of crystal was grown by the vertical Bridgeman(VB)method. Based on the theoretical analysis of VGF and VB crystal growth method, the crystallization rate of the 6-inch GaAs crystal was increased to more than 48% by optimizing the support structure, increasing the cooling rate of VGF crystal growth and optimizing the growth rate of VB crystal. Based on the compensation theory of semi-insulating GaAs, the resistivity of the crystal was increased to more than 4×10^7 Ω·cm and the heterogeneity of resistivity was reduced to less than 25% by doping excessive carbon powders and El2 controlling. The dislocation density of the GaAs single crystal was reduced to less than 104 cm^-2 by optimizing the growth interface.

关 键 词：GAAS 半绝缘单晶 单晶生长 垂直梯度凝固(VGF)法 垂直布里奇曼(VB)法 

分 类 号：TN304.2[电子电信—物理电子学]