Substrate misorientation dependence of thermal stability of Si atom in Si atomic layer doped GaAs on GaAs(111)A

The effects of off-angle of misoriented GaAs(111)A substrates on the thermal stability of Si atoms in Si atomic layer doped GaAs layers have been investigated by SIMS. This off-angle is found to strongly affect diffusivity; the diffusion coefficient for exactly (111)A is the smallest, and becomes large as the off-angle increases in the [110] or [001] direction. Such a diffusivity dependence can be understood by the density of the step, which is caused by substrate misorientation. Furthermore, the diffusivity of Si depends on the occupation site of Si; Si atoms in p-type layers where the Si occupies As sites are more stable than Si atoms in n-type layers where the Si occupies Ga sites. These results show that Si δ-doped layers on (111)A are suitable as p-type doped thin layers with their low diffusivity in electronic devices