用微波光电导谱仪测量p—n结少子扩散长度

Measuring p-n Junction Minority Carrier Diffusion Length by Microwave Photoconductivity Spectrum Instrument

用微波光电导谱仪测量了一些pn结样品的微波光电导谱(MPCS),对于每一块样品光分别从p面和n面入射,因而可以测得不同的谱;讨论了从pn结的MPCS中计算p区、n区少子扩散长度的方法,并用计算机拟合得到这些样品的p区、n区少子扩散长度和表面复合速度等参数;由于是无接触测试,因此本方法可作为某些pn结器件制造工艺过程中寻找最佳工艺条件的一种监测手段。

We have measured microwave photoconductivity spectrum (MPCS) of some silicon p-njunction samples by microwave photoconductivity spectrum instrument.These MPCS arequite different when the sample was illuminated by light from p-region or n-region seperately.This paper presents a method of calculating the minority carrier diffusion length of the p-regionand n-region from their MPCS. Meanwhile the parameters of these samples, such. as as surfacerecombination velocity etc. , are given by nonlinear fitting method. Because it is a contactlessmeasurement, we can use this method as a monitor in the process of manufacturing pnjunction devices.