Proton implantation for isolation of n-type GaAs layers at different substrate temperatures

摘要

The effects of dynamic annealing of damage-induced defects during implantation at elevated temperatures have been investigated in proton-isolated n-type GaAs layers. The results were compared with those obtained at nominal room temperature. The n-type material was prepared using multi-energy implants of ~29Si~+ ions. The isolation implants were performed using 3 x 10~14 cm~-2, 500 keV H_2~+ ions at temperatures of either RT, 100 or 200 ℃. After implantation, samples were annealed in order to investigate the evolution of sheet resistivity. Maximum resistivity values were achieved after annealing at 350 ℃ for RT and elevated-temperature implants. Annealing at higher temperatures returned the resistivity to a value close to that of the starting material and this recovery of conductivity was fastest in the case of RT implants. It is thought that the different thermal stability of defects generates different trap structures that may lead to different behaviour in the evolution of sheet resistivity tbr samples implanted at 100 or 200 ℃.