Radiation Effects in ALUMINUM(X)GALLIUM(1-X)ARSENIDE and Indium-Phosphorus

Available from UMI in association with The British Library. Radiation effects in Al_{ rm x}Ga_{rm 1-x}As and InP produced by hydrogen ion bombardment have been studied using mainly electrical resistivity measurements and thermal annealing techniques. Multiple energy ion bombardments at 400 keV to 100 keV were used in most experiments at beam power densities of below 100 mW cm^{-2}. Two terminal, through layer, resistivity measurements were made on Al_{rm x}Ga _{rm 1-x}As:Se with Al mole fraction, x, from 0 (GaAs) to 0.82. In all cases, a maximum resistivity of 1E8 to 1E10 ohm cm was achieved with proton or deuteron bombardment. As x is increased from 0 the resistivity maximum rises gradually from 1E8 to 1E10 ohm cm at x = 0.45 and then gently falls. This behaviour has been explained by considering a single deep level with an activation energy which varies with x in a similar manner to that of the shallow donor levels in Al_{rm x}Ga _{rm 1-x}As. Using an interdigital contact geometry, the first in-situ measurements of the change in Al_ {rm x}Ga_{rm 1-x}As resistivity with ion dose have been made. This has enabled repeated irradiation-measurement cycles, resulting in a rapid determination of the resistivity behaviour and a more accurate measurement of the optimum ion dose for maximum resistivity. The observed anomalously efficient carrier removal of deuterons in GaAs:Si has not been observed in any GaAs:Se or Al_{rm x}Ga _{rm 1-x}As:Se. Proton bombardment is less efficient in GaAs:Si than in GaAs:Se, perhaps due to a parasitic interaction of the protons with the silicon donor species. The thermal stability of the isolation in Al _{rm x}Ga_ {rm 1-x}As:Se, over the whole composition range, appears to be suitable for device applications if post-implant process steps are kept below 400^ circC. Whilst the isolation in InP was observed to be stable to up to 300^circC, some indications of room temperature annealing were noted. The electrical properties of proton and deuteron bombarded material appear to be closely similar. However, preliminary Rutherford Back Scattering (RBS) and optical absorption measurements on Al_{rm x}Ga_{rm 1-x} As samples have indicated differences. RBS has shown the level of disorder introduced by deuteron bombardments to be slightly higher than expected compared with proton bombardments. Optical absorption has shown the optical activity of the deuteron induced damage to be more intense. (Abstract shortened by UMI.).