ANNEALING BEHAVIOR OF HF-TREATED GAAS CAPPED WITH SIO2-FILMS PREPARED BY 50-HZ PLASMA-ASSISTED CHEMICAL VAPOR-DEPOSITION

Thermal stability of the SiO2/GaAs interface structures prepared by 50-Hz plasma-assisted chemical vapor deposition (PCVD) and the electrical activation of Si implanted into GaAs with SiO2 cap were investigated. X-ray photoelectron spectroscopy (XPS) analysis showed that the 50-Hz PCVD method at 200-degrees-C allowed the presence of an As-enriched layer, intentionally inserted by HF treatment before SiO2 deposition, at the SiO2/GaAs interface. After rapid thermal annealing (RTA) at 950-degrees-C for 20 s, in fact, the As-enriched layer still remained and it was effective in suppressing interfacial reactions which caused various shortcomings. In addition, carrier concentration profiles in excellent agreement with Lindhard-Scharff-Schiott (LSS) curves were reproducibly obtained by RTA in Si-implanted GaAs capped with both the As-enriched layer and the SiO2 film, demonstrating that this process is applicable to post-annealing of ion-implanted GaAs.