The Rapid Amorphisation of In 0.53 Ga 0.47 As relative to Both InAS and GaAs

Abstract

Rutherford backscattering spectrometry in combination with channeling has been used to compare the ion-irradiation-induced amorphisation of In 0.53Ga0.47As with that of InAs and GaAs. In contrast to the well-known behaviour of AlxGa1-xAs, the ternary alloy In0.53Ga0.47As did not exhibit amorphisation kinetics intermediate between those of the two binary extremes. Specifically, the critical nuclear energy deposition required to render In0.53Ga 0.47As amorphous was less than that of both InAs and GaAs for irradiation temperatures of -196°C and 23°C. This rapid amorphisation resulted from a greater probability for direct-impact amorphisation in the ternary alloy. We suggest irradiation-induced defect clusters or amorphous nuclei in In0.53Ga0.47As serve as a means of relieving strain and accordingly exhibit enhanced stability. Such strain is present in the ternary alloy, at the atomic scale, due to the significant differences in In-As and Ga-As bond lengths and the random ordering of In and Ga on the Group III sub-lattice and is manifested by a broadening of the bond length and bond angle distributions.