Damage distribution and measure of projected range in proton bombarded GaAs

Abstract

The technique of cross-sectional transmission electron microscopy has been applied to obtain information on the projected range of protons and their damage distribution in gallium arsenide. The crystals were subjected to dosages of 1 × 10¹⁵ to 1 × 10¹⁷ protons cm⁻² and proton energies of 100, 200 and 300 keV. Within this energy range the damage shows a Gaussian distribution about a mean range which correlates closely with LSS values. The experimentally determined damage profiles are found to be essentially independent of proton energy and the temperature of post implantation anneal for a given dosage. The displacement damage as reflected by the damage profiles is found to be linear with proton dose. Finally, it is estimated that defects became visible in unannealed crystals when each atom is, on the average, displaced at least once during irradiation.