Quantitative determination of microdefect density in dislocation-free silicon by preferential chemical etching

Abstract

A phenomenological equation is derived which relates the observed surface density of hillock defects in dislocation-free Czochralski silicon crystals to the bulk density, the etch rate, the etch time and a parameter which we call the defect survival time which is defined as the time interval between the defect being revealed by the etch and the feature being totally etched away. Application of a practical method, designated etching analysis with time (EAT), to the quantitative analysis of two silicon samples from the same dislocation-free crystal is described. Excellent agreement between theory and experiment is obtained.