低位错锗单晶片的表面位错腐蚀研究  

Surface Dislocation Corrosion in Germanium Monocrystal Wafer of Low Dislocation Density

作　　者：张路 霍承松 马远飞 马会超 林泉 冯德伸 Zhang Lu;Huo Chengsong;Ma Yuanfei;Ma Huichao;Lin Quan;Feng Deshen(Beijing Guojing Infrared Optical Technology Co.,Ltd.,Bejing 100088,China;GRINM Electro-Optic Materials Co.,Ltd.,Langfang 065001,China)

机构地区：[1]北京国晶辉红外光学科技有限公司,北京100088 [2]有研光电新材料有限责任公司,河北廊坊065001

出　　处：《稀有金属》2022年第8期1118-1124,共7页Chinese Journal of Rare Metals

基　　金：河北省科技计划项目(19011111Z)资助。

摘　　要：锗单晶在红外以及空间太阳能电池都有广泛应用。目前,超过90%的空间电源都是锗基太阳能电池,使得低位错锗单晶成为空间太阳能电池的基础材料。太阳能电池使用的锗单晶要求位错密度低于1000 cm^(-2),高效电池甚至要求单晶位错密度低于300 cm^(-2),其对锗单晶片内部的位错数量要求不断提高,对位错密度测量精度提出更高的要求。采用HNO_(3)-HF体系的抛光腐蚀液对锗单晶片进行处理,通过择优腐蚀显示位错。通过改变金刚砂粒度、抛光温度、抛光时间、腐蚀温度、腐蚀时间、晶向偏离角度等条件,从表面粗糙度及金相图表面形貌等方面进行了比较和分析,确定了不同条件下的锗单晶片抛光腐蚀情况,以及晶向偏离角度大小对位错密度偏差的影响。结果表明,采用本文确定的切割、研磨、表面腐蚀方法,位错形貌清晰显现完全,位错测量误差可以控制在5.5%以内,能够保证测量精密度。为实际应用中锗材料位错密度测量及腐蚀工艺的改进提供实验依据及理论参考。Low dislocation germanium monocrystal is the basic material of optoelectronics and microelectronics.It is widely used in space solar cell,ground solar cell(CPV),high brightness LED and other semiconductor devices.The conversion efficiency of GaAs solar cells with germanium as substrate is as high as 30%,which is much higher than that of silicon solar cells,replacing the application of silicon solar cells in space.At present,more than 90%of space power supply is germanium based solar cells,which makes it the basic material of space solar cells.The dislocation density of germanium monocrystal used in space solar cells is required to be less than 1000/cm^(2),and even lower than 300/cm^(2)for high-efficiency cells.Dislocation is a common defect in germanium monocrystal.The existence of dislocation has a great influence on the electrical properties of materials and device parameters.Dislocations distort the lattice,change the energy band position and affect the carrier recombination process.Edge dislocation can reduce the minority carrier lifetime and accelerate the diffusion of impurities in germanium single crystal.The inhomogeneous dislocations can even disperse the device parameters.When the dislocation pile is formed,it will affect the p-n junction and cause local breakdown of the device.High or uneven dislocation density will seriously affect the photoelectric conversion efficiency and service life of solar cells.So,the requirement of inner number of dislocations for germanium monocrystal wafer and measurement accuracy of dislocation density get more and more attention.The inaccuracy of dislocation density measurement may directly affect the quality of battery products,which is easy to cause the contradiction between supply and demand,and has an impact on the sales and application of products.In this paper,germanium monocrystal wafer was mainly corroded by HNO_(3)-HF system,then displayed dislocations through preferential corrosion.By changing the factors in particle size of carborundum,polishing temperature,pol

关 键 词：锗单晶 位错密度 抛光 腐蚀 偏离角度 

分 类 号：TN304.1[电子电信—物理电子学]