Nonradiative recombination at GaAs homointerfaces fabricated using an As cap deposition/removal process

Abstract

GaAs homointerfaces have been grown by molecular beam epitaxy using the steps of GaAs growth, As cap deposition, wafer storage, thermal desorption of the As cap, and GaAs overgrowth. As cap layers with a thickness of up to 7.8 μm were deposited and the wafers were stored for 3–7 days in ultrahigh vacuum (UHV) or under atmospheric conditions. Nonradiative recombination originating from the GaAs homointerface of wafers stored in UHV could not be detected (interface recombination velocity S≪1000 cm/s), however, significant nonradiative recombination (S=104–105 cm/s) was found for all GaAs homointerfaces where wafer storage occurred under atmospheric conditions. This result demonstrates that the As cap deposition/removal process is inadequate for GaAs surface protection in a fabrication facility.

Very-low-temperature molecular beam epitaxial growth of GaP/AlAs heterostructures for distributed Bragg reflector applications

“…The substrate temperature variations would affect the sticking coefficients of the As at lower temperatures. Studies have shown that the sticking coefficient is nearly exponential with temperature at these low temperatures, 8 so a 10°C variation in substrate temperature could affect the growth rates. Also, the Ascracking cell showed some instability in the As flux during growth.…”

Role of Ga2O3 template thickness and gadolinium mole fraction in GdxGa0.4−xO0.6/Ga2O3 gate dielectric stacks on GaAs

“…Subsequent to epitaxial layer growth, the GaAs surface was covered by a protective arsenic cap layer. 10 After loading the wafer into another ultrahigh vacuum chamber, the As cap layer was desorbed and Ga 2 O 3 template growth commenced ͑except when no Ga 2 O 3 template was grown͒ using effusive evaporation of a polycrystalline Ga 2 O 3 source material from a high temperature effusion cell. Ga 2 O 3 template thickness ranges from 0 to 72.8 Å in this study.…”