LOW D-IT, THERMODYNAMICALLY STABLE GA2O3-GAAS INTERFACES - FABRICATION, CHARACTERIZATION, AND MODELING

Thermodynamically stable, low D-it amorphous Ga2O3-(100) GaAs interfac es have been fabricated by extending molecular beam epitaxy (MBE) rela ted techniques, We have investigated both in situ and ex situ Ga2O3 de position schemes utilizing molecular beams of gallium oxide. The in si tu technique employs Ga2O3 deposition on freshly grown, atomically ord ered (100) GaAs epitaxial films in ultrahigh vacuum (UHV); the ex situ approach is based on thermal desorption of native GaAs oxides in UHV prior to Ga2O3 deposition, Unique electronic interface properties have been demonstrated for in situ fabricated Ga2O3-GaAs interfaces includ ing a midgap interface state density D-it in the low 10(10) cm(-2) eV( -1) range and an interface recombination velocity S of 4000 cm/s. The existence of strong inversion in both n- and p-type Gals has been clea rly established, We will also discuss the excellent thermodynamic and photochemical interface stability, Ex situ fabricated Ga2O3-GaAs inter faces are inferior but still of a high quality with S = 9000 cm/s and a corresponding D-it in the upper 10(10) cm(-2)eV(-1) range. We also d eveloped a new numerical heterostructure model for the evaluation of c apacitance-voltage (C-V), conductance-voltage (G-V), and photoluminesc ence (PL) data The model involves selfconsistent interface analysis of electrical and optoelectronic measurement data and is tailored to the specifics of GaAs such as band-to-band luminescence and long minority carrier response time tau(R). We will further discuss equivalent circ uits in strong inversion considering minority carrier generation using low-intensity light illumination.