NUMERICAL FITTING OF TRANSIENT DECAYS IN THE HIGH DEFECT DENSITY LIMIT

A numerical fitting method based on the deep level transient spectrosc opy (DLTS) technique is presented. This method deals with a situation where the standard rate window DLTS is no longer sufficient, i.e., the assumption that the defect density N(T) is much less than the donor d oping density N(D) is no longer valid. Digitized capacitance transient s are numerically fit to extract the electron emission rate, defect de nsity, and energy level. The defect center under study is EL2 in n-typ e liquid-encapsulated Czochralski gallium arsenide. The fitting method gives an EL2 thermal activation energy of 0.76 eV, different from the 0.82 eV obtained by standard DLTS, which only examines the maximum em ission conditions. The advantages, as well as the limitations, of this fitting method are discussed.