Determining the Surface Doping Concentration in Semiconductors
Original Publication Date: 1978-May-01
Included in the Prior Art Database: 2005-Feb-20
In a silicon (Si) wafer with an unknown surface concentration of electrically active atoms, different doses of an element of the opposite doping type are implanted at several points at an energy which is such that the maximum of the implantation peak is at the Si-SiO(2) interface. For this purpose, an SiO(2) layer, which is pyrolytically generated, or an existing thermally generated SiO(2) or Si(3)N(4) layer can be used. After the SiO(2) layer has been stripped, the Si wafer is annealed. During this treatment an inversion, which is made visible with the aid of a staining solution, occurs in places with excessively implanted atoms. The surface concentration c(o) can be directly read.