Metal-insulator-semiconductor structures on p-type GaAs with low interface state density

Interfacial properties of in situ deposited Si₃N₄/Si/p-GaAs metal-insulator-semiconductor structures have been investigated. Conductance loss measurements show that a minimum interface trap density as low as 5.5X10¹⁰ cm^-1 eV^-1 has been achieved on p-type GaAs by using a high quality strained Si interlayer. The quasistatic and high-frequency capacitance-voltage measurements as well as the theoretical high-frequency capacitance-voltage calculation clearly demonstrate the accumulation, depletion, and inversion regions. The interface trap density as a function of the band-gap energy near the midgap has been determined with the conductance method. The reduced band bending (0.84 V) may be mainly caused by the narrower band gap of the strained Si interlayer.