Проводимость гетеропереходов Ga-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=--GaAs

Abstract

AbstractThe effect of annealing in argon at temperatures of T _an = 700–900°C on the I – V characteristics of metal–Ga_2O_3–GaAs structures is investigated. Samples are prepared by the thermal deposition of Ga_2O_3 powder onto GaAs wafers with a donor concentration of N _ d = 2 × 10^16 cm^–3. To measure the I – V characteristics, V/Ni metal electrodes are deposited: the upper electrode (gate) is formed on the Ga_2O_3 film through masks with an area of S _ k = 1.04 × 10^–2 cm^2 and the lower electrode in the form of a continuous metallic film is deposited onto GaAs. After annealing in argon at T _an ≥ 700°C, the Ga_2O_3- n -GaAs structures acquire the properties of isotype n -heterojunctions. It is demonstrated that the conductivity of the structures at positive gate potentials is determined by the thermionic emission from GaAs to Ga_2O_3. Under negative biases, current growth with an increase in the voltage and temperature is caused by field-assisted thermal emission in gallium arsenide. In the range of high electric fields, electron phonon-assisted tunneling through the top of the potential barrier is dominant. High-temperature annealing does not change the electron density in the oxide film, but affects the energy density of surface states at the GaAs–Ga_2O_3 interface.