Nondestructive techniques for investigating semi-insulating gallium arsenide as initial material for direct implantation

Abstract

The analysis of the effect of initial semi-insulating gallium arsenide quality on microwave ion-implanted metal- semiconductor field-effect transistors (MESFETs) parameters has been carried out. The leakage current method, `photofield-effect transistor with bias on substrate' technique for MESFET structures on GaAs wafers, Hall measurements, optical absorption, photoluminescence, ellipsometry have been used for evaluating semi-insulating gallium arsenide quality. The criteria for sorting initial semi-insulating gallium arsenide as material applicable to direct ion implantation in the process of microwave MESFETs and integrated circuits fabrication have been developed. The possibilities of prognosticating MESFET parameters and their thermal stability are defined by the compensation scheme taking into consideration the presence of deep impurity levels, deep level concentration and peculiarities of their distribution along ingot length and along wafer diameter as well as deep level redistribution during annealing.