Easy and accurate method to determine simultaneously the free energy level and the capture cross section of a trap centre

Abstract

A method which permits simultaneous determination of the values of the free energy of ionization, the capture cross section and the concentration of a trap in a semiconductor is presented. The method depends on an accurate fit of a set of analytical expressions to the experimental data obtained by studying the variation of transient capacitance amplitudes with the duration of a filling pulse bias in a junction experiment. The analytical expressions used are based on the rigorous theoretical model of Pons. Various criteria which must be observed to ensure reliable results are carefully worked out in detail. The effectiveness of the present method is demonstrated on two copper-induced electron traps in gallium arsenide phosphide and a laser radiation-induced electron trap in silicon.