Abstract: Based on the basic principle of minority carrier lifetime measurement of semiconductor by high frequency photoconductive attenuation method,a minority carrier lifetime measurement system is designed,and the signal processing system is improved on the basis of the diode detection circuit.Compared with the traditional diode detection circuit,the feedback principle of the operational amplifier eliminates the error caused by the voltage drop of the detector diode.At the same time,the effect of the voltage swing rate of the operational amplifier is reduced by the diode embedding effect,which further improves the detection ability of the measurement system.In addition,the feasibility of the detection circuit is verified by experiments,which effectively improves the accuracy of the measurement system.

Key words: High frequency photoconductive attenuation method, Lifetime of the few children, Signal processing, Operational amplifier