GROWTH OF ZN DELTA-DOPED ALXGA1-XAS BY LOW-PRESSURE METAL-ORGANIC VAPOR-PHASE EPITAXY

A very significant Zn evaporation from nongrowing Al1-xGa1-xAs surface during a post-delta-doping purge step was observed in growth of Zn delta-doped AlxGa1-xAs (x<0.65) by low pressure metal organic vapor phase epitaxy using dimethylzinc as a doping precursor. A delta-doping sequence different from the normal ''purge-doping-purge'' is therefore proposed to minimize the Zn evaporation. Using this delta-doping sequence, the dopant memory effect was investigated and the best hole profile of Zn delta-doped GaAs (Al0.35Ga0.65As) was obtained,having a full width at half-maximum of 7.0 nm for a peak concentration of 1.1X10(20) cm(-3) (13 nm for 4.8X10(18) cm(-3)). It was found that the growth temperature significantly influences the hole concentration of Zn delta-doped GaAs and the hole concentration decreases and the hole profile width increases with increasing Al content of Zn delta-doped AlxGa1-xAs. (C) 1995 American Institute of Physics.