表面损伤层对Hg1-xMnxTe晶片电学参数的影响

Effect of Surface Damaged Layers on the Electronic Properties of Hg1-xMnxTe Wafers

摘要:

采用范德堡法在77K下对多个Hg1-xMnxTe晶片化学抛光前后的电学性能进行了Hall测量。结果发现：与化学抛光后所测值相比，抛光前所测得的电阻率和霍尔系数值相对较小，而霍尔迁移率和载流子浓度相对较大，其中电阻率和霍尔迁移率在化学抛光前后变化幅度分别高达25％和31％，而霍尔系数和载流子浓度的变化幅度只有2％左右。化学抛光前，晶片表面损伤层内存在大量位错，对载流子的迁移造成散射，使得损伤层中的霍尔迁移率降低，但化学抛光前所测得的霍尔迁移率反而比抛光后的大，增幅最小的也达到了21％。本研究在3层模型的基础上，通过理论分析和计算，对这一反常现象以及化学抛光前后其它电学参数的变化进行了解释。

Abstract:

Electronic properties of several Hg1-xMnxTe wafers before and after chemical polish were characterized by Van Der Pauw method at 77 K. Results showed that values of resistivity and Hall coefficient of the wafers before etching are lower than those after etching, while Hall mobility and carrier density were higher. The maximum of resistivity decreased by 25%, the maximum of Hall mobility increased by 31%, but Hall coefficient and carrier density changed only by about 2% before and after etching. There existed a lot of dislocations in surface damaged layer, resulting in the decrease of Hall mobility of charge carrier, but the values of Hall mobility of wafers before chemical polish were higher, the minimum of which increased by 21%. It is a abnormal phenomena. All the experimental results can be explained using a three-layer model.