高频光电导衰减法测试Ge单晶少数载流子寿命

Measurement of Minority-Carrier Lifetime in Ge by High Frequency Photoconductivity Decay

高频光电导衰减法是测量Ge单晶少数载流子寿命常用的方法,高频脉冲信号照射到单晶表面时,产生非平衡载流子,非平衡载流子的复合时间长短反映了少数载流子寿命的大小。电阻率越低,少数载流子寿命越小,仪器就难以测试。介绍了电阻率为0.03~0.04Ω.cm Ge单晶少数载流子寿命的测试方法。通过理论分析及实际测试,发现影响Ge单晶测试的主要因素有3个,即样品的表面状态、厚度及测试仪器的小注入水平。通过规范这些测试条件,能够测试低阻Ge单晶的少数载流子寿命。

The high frequency photoeonductivity decay is the common method to measure the minoritycarrier lifetime in Ge. When the high frequency pulse irradiates the Ge surface, non-equilibrium carriers are generated. The existence period of non-equilibrium carriers reflects the minority-carrier lifetime. When the resistivity is lower, the minority-carrier lifetime is lower, and the measurement is more difficult. The measurement of Ge with the resistivity 0.03 - 0.04 12＂ cm was discussed. Through the test process, three factors to influence the results were found, including the surface state, thickness and the quantity of photo injection. With the criterion of measurement conditions, the minority-cartier lifetime of Ge with the low resistivity could be tested.