Effect of Al-rich surface on Se delta-doped GaAs grown by low-pressure metalorganic chemical vapor deposition

We study Se delta-doped GaAs grown by low-pressure metalorganic chemical vapor deposition using hydrogen selenide as a doping precursor. The results of capacitance-voltage measurements show that the very sharp doping profile can be obtained by Se delta-doping on an Al-rich surface and Se segregation is also reduced by making an Al-rich surface after delta-doping. It is essential to utilize the delta-doping sequence which does not have a post-delta-doping purge step to minimize the Se evaporation. (C) 1996 American Institute of Physics.