A method for contactless measurement of electrical conductivity of Si wafers independent of wafer thickness is presented. The effective region within which this proposed technique can be used is discussed in detail, and an equation to determine the boundary of the effective region is introduced. Three groups of Si wafers with different thicknesses were used as samples. A compact microwave instrument working at 94 GHz was used to measure the samples without contact. The reflection coefficient of the microwave signal was obtained and used to determine the electrical conductivity of the wafers. The electrical conductivities of the wafers thus measured were in good agreement with values obtained using a conventional four-point-probe method. This indicates that the proposed technique is a powerful tool for contactless measurement of electrical conductivity of Si as well as other semiconductor wafers independent of wafer thickness.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)