Ga~+ion beam induced compositional intermixing in MBE grown Al_xGa_(1-x)As/GaAs quantum wells: optimization of the structural parameters for low dose applications

摘要

Ion implantation into quantum wells (QWs) and subsequent rapid thermal annealing allows one to generate lateral structures with very high resolution. To reduce damage to the crystal structure, it is important to keep the ion dose as small as possible. Compared with earlier works, we have been able to reduce the dose by one to two orders of magnitude by optimizing the structural parameters of the samples. Using 100 keV Ga~+ ions and Al_xGa_(1-x)As/GaAs quantum wells, we obtained the best results for a superlattice barrier with a period of 2.8 nm. The interdiffusion length of about 1.3 nm at a depth of about 70 nm was obtained for doses as low as 7x10~(12) cm~(-2) using moderate annealing temperature (750deg C) and duration (20s).