Ion-beam-induced epitaxial crystallization of amorphous GaAs on GaAs(100)

Abstract

Epitaxial crystallization of deposited amorphous GaAs layers on GaAs(100) up to the surface by bombardments with 400 keV Ar and 400 keV Kr has been successfully performed at a temperature range between 125 and 200°C. Properties of crystal growth were investigated as a function of ion species (Ar and Kr), energy (400 and 800 keV), ion dose, dose rate and substrate temperature by RBS channeling experiments. The growth rate has shown a nearly linear dependence on ion fluence. Ion bombardments below 100°C have induced further amorphization beyond the initial crystal/amorphous interface. On the scale of nuclear energy deposition density, bombardments with higher electronic excitation efficiency give a small increase of the growth rate. Ar bombardments have shown a strong dependence of the growth rate on dose rate, whereas Kr bombardments have revealed a weak dependence. An apparent activation energy of 0.13 ± 0.06 eV for the crystal growth was observed.