Patent ID: 6534774
Filing Date: 2003-03-18
Classification: G01N

Abstract:
A method for evaluating the quality of a semiconductor substrate, comprising the steps of;irradiating intermittently the surface of a semiconductor substrate with an excitation light, converting the intensity of a photoluminescence light emitted by said semiconductor substrate when said semiconductor substrate is intermittently irradiated with said excitation light into an electric signal, obtaining the decay time constant of the photoluminescence light from variation of the average intensity of the photoluminescence light converted into said electric signal by increasing gradually the chopping frequency of the excitation light, and computing a life time being an indicator of evaluation of the quality of said semiconductor substrate from an expression (1): &tgr;=T/Câ€ƒâ€ƒ(1), where &tgr; is a life time, T is the decay time constant of a photoluminescence and C is a constant.