Patent ID: 7804294

Claim:
A contactless sheet resistance measurement method, comprising the steps of: illumination the area of the semiconductor structure through a transparent electrode with intensity modulated light at maximum frequency corresponding to bandwidth of SPV preamplifier and lock-in amplifier; measurement of the SPV signal, Vs 1 , from the transparent electrode; adjustment of the light flux to get linear dependence of the SPV signal, Vs 1 , versus light flux; measurement of SPV signals, Vs 1 and Vs 2 ; adjustment of light modulating frequency to get the ratio of SPV signals RATIO=Vs 1 /Vs 2 <5 and measurement of Vs 1 and Vs 2 at this frequency; and determination of the sheet resistance using measured RATIO=Vs 1 /Vs 2 , and the calculated curve or table RATIO(Rs).