Heavy metal contamination evaluation method null of the compound semiconductor substrate

摘要

PURPOSE:To simply evaluate the heavy metal pollution at the surface of a substrate by dividing a GaAs compound semiconductor substrate into two, and cleaning the surface of a first divided wafer and measuring the average carrier concentration, end for a second divided wafer, measuring the average carrier concentration as it is, and using the surface pollution parameter expressed by a specific formula. CONSTITUTION:When evaluating the heavy metal pollution on the surface of a GaAs compound semiconductor single crystal substrate, the substrate is divided into two, and surface of a first divided wafer, is cleaned and further after heat-treating it under fixed conditions, the surface layer is removed, and the average carrier concentration ne is measured, and a second divided wafer is heat-treated under the same conditions as the first divided wafer as it is and similarly the surface layer is removed, and the average carrier concentration na is measured, and the surface pollution parameter kappaexpressed by formula kappa=(ne/na)-1 is used. Hereupon, it means that the greater the surface pollution parameter kappa is, the greater the heavy metal pollution is, and that the smaller kappa is, the smaller the heavy metal pollution is. Hereby, the degree of the pollution of heavy metal the surface of the substrate can be evaluated simply.