M. Passlack et al., LOW D-IT, THERMODYNAMICALLY STABLE GA2O3-GAAS INTERFACES - FABRICATION, CHARACTERIZATION, AND MODELING, I.E.E.E. transactions on electron devices, 44(2), 1997, pp. 214-225
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.