Characterization of an aging effect in high purity indium phosphide

Changes in the characteristics of high-purity n-type InP samples with time have been studied using variable-temperature Hall effect measurements, photoluminescence, and photothermal ionization spectroscopy. The results indicate that the aging effect is a bulk effect and that it results from a major reduction in N/sub D/. The aging effect can be reversed by a short anneal at a temperature above 170 degrees C. The spectroscopy results show that the change in N/sub D/ is due entirely to a change in the Si shallow donor concentration. However, the mechanism of reduction of the shallow Si donor concentration with aging remains unknown. It seems probable that a limited concentration of unknown defect centers is involved and that the Si donors combine with these unknown defect centers to form inactive centers or to change the Si donor binding energy from shallow to deep level.<>