Doping method for GaAs molecular-layer epitaxy by adsorption control of impurity precursor

The doping mechanism of Se and Te in GaAs molecular-layer epitaxy (MLE) was examined by the timing of supply of the impurity precursor on each orienta tion of the substrate. On (0 0 1) GaAs, the impurity incorporation on the g rowing surface may be prevented by AsHx (x = 0, 1, 2, 3) adsorbed during th e AsH3 supply, and is apt to be promoted on a Ga-terminated surface. For ea ch orientation of the substrate, the doping characteristics differ noticeab ly. On the (1 1 1)A surface, Te is incorporated at the lowest temperature, while it is incorporated at the highest temperature on (1 1 1)B. It was cla rified that Control of the adsorption of impurity precursor is an essential factor in the precise control of doping in MLE. (C) 2001 Elsevier Science B.V. All rights reserved.