AC profiling by Schottky gated cloverleaf

Publisher Website
Google Scholar
Abstract
Depletion type profiling methods offer clear advantages over stripping techniques provided that depletion of the region of interest can be attained without the surface field exceeding the critical value for the material under test. Two well known methods are (i) differential CV measurements by which n(x) may be determined with a high degree of accuracy, and (ii) stepwise depletion from a Schottky or MOS gate suitably located in a sample in Hall geometry by which n(x) and mu (x) can be measured less accurately. The author outlines a method combining virtues of both approaches in which the stepped d.c. applied to the Schottky gate on a van der Pauw cloverleaf is modulated by an a.c. signal and a.c. components of Hall and van der Pauw voltages are synchronously detected. Equations governing the extraction of mu (x) and n(x) from the data are given and two sample experimental results presented.