A new method of measuring interface state densities in mis devices

Abstract

A capacitance derivative technique for measuring interface (surface) state densities in MIS devices is presented. The capacitance derivative spectrum is analytically shown to be very sensitive to surface state influences. Experimentally, the spectrum is accurately obtainable with a phase-sensitive harmonic analysis scheme. It is found that midgap surface state densities to 10 10 cm −2 eV −1 can be rapidly estimated. A detailed energy distribution throughout much of the gap can also be found but with somewhat more difficulty. The ease with which surface state densities can be measured with this method could facilitate the monitoring of silicon-silicon dioxide interface quality in routine production.