Nitrogen Atomic-Layer-Doping on Ga-Terminated and Misoriented GaAs Surfaces by Metalorganic Vapor Phase Epitaxy Using Dimethylhydrazine

Nitrogen atomic-layer-doping on Ga-terminated and misoriented GaAs surfaces was performed by Metalorganic Vapor Phase Epitaxy (MOVPE) using dimethylhydrazine to investigate the role of the surface for nitrogen atom incorporation. Compared with the As-terminated surface, dimethylhydrazine molecules are preferentially decomposed on the Ga-terminated surface due to the catalytic effect, resulting in a higher doping efficiency. We also investigated the crystal orientation dependence of the nitrogen doping concentration. Nitrogen atoms are preferentially incorporated on the (n11)A surfaces (n≥3) than the (100) surface. For the (n11)A surface, the nitrogen doping efficiency increases with decreasing n value. This indicated the doping efficiency increases with the step density. In contrast, nitrogen atoms are incorporated less on the (n11)B surfaces (n≥3) than the (100) surface and their doping efficiency decreases with increasing step density. These results are ascribed to the difference of atomic bonding geometries for adsorption sites between (n11)A and (n11)B surfaces. The doping efficiency for A-type steps is twice as high as that for the (100) terraces while that for B-type steps is negligibly small.