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Abstract

This invention discloses a method for contactless evaluation of characteristics of semiconductor wafers and devices. The method includes the steps of (a) continuously irradiating focused microwaves on a surface of a semiconductor specimen; (b) continuously receiving reflected microwaves reflected from said surface; (c) irradiating a focused laser beam pulse on the specimen, energy of the pulse being in excess of the band-gap energy of the semiconductor material; (d) measuring lifetime .tau..sub.m from the time-history of the characteristics of the reflected microwaves; and (e) calculating the surface recombination velocity S and bulk lifetime .tau..sub.b. The focused microwaves and focused laser beam can improve the resolution during measurement. Furthermore, the method includes the steps of: (a) continuously irradiating microwaves on a surface of a semiconductor specimen; (b) continuously receiving reflected microwaves reflected from said surface; (c) irradiating a laser beam pulse on the specimen, energy of the pulse being in excess of the band-gap energy of the semiconductor material; and (d) changing the characteristic of the reflected microwaves to an electrical signal, for obtaining the intensity of the reflected microwaves at a predetermined moment, repeating those steps at a plurality of points on the surface, thereby obtaining electrical signals at the points according to surface recombination velocities S at the points, so that the surface condition of the specimen can be evaluated.

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First Claim