Wire-Like Doping Of Si Atoms At Multiatomic Steps On GaAs[001] Vicinal Surfaces By Metalorganic Vapor Phase Epitaxial Growth

Atomically control of the incorporation sites of impurity atoms on the semiconductor surfaces is important for the fabrication of ultimate nano-scale devices. One of the approaches for such purpose is to utilize multi-atomic steps, which are naturally formed on vicinal surfaces with fairly regular spacing during metalorganic vapor phase epitaxial growth (MOVPE) [ l ] . Here we report on the 8 doping of Si on MOVPE grown GaAs vicinal surface, and explore the possibility of selective incorporation of Si along atomic steps. The growth was carried out in a low-pressure MOVPE system with triethylgallium (TEGa), triethylaluminium (TEAI), and arsine (ASH,) as source materials and monosilane (SiH,) as a dopant. toward the[-1101 direction (6 step). The layer sequence and the sample structure are schematically shown in Fig.1. Following GaAs and (AIAs),(GaAs), buffer layers, thick GaAs layer was grown at 600°C in order to form multi-atomic steps on the surface. Next, samples were annealed at 600°C for 30min to form uniform multiatomic steps with equal distance. Si 6 doping layer was formed at 600°C by supplying SiH, under arsine atmosphere during growth interruption. The doping times were changed from 10sec to 1000sec. SiH, partial pressure was kept at 1.25 X lO-'atm. Finally, 500nm undoped GaAs layer was grown as a cap layer at 550°C. The main results are listed below. Substrates were vicinal (001) GaAs with misorientation angles, a of 0" to 5.0"