Characteristics of Si3N4/Si/n-GaAs metal-insulator-semiconductor interfaces grown on GaAs(111)B substrate

Interfacial properties of Al/Si3N(4)/Si/n-GaAs metal-insulator-semiconductor (MIS) capacitors grown on GaAs(111)B prepared with a combination of in situ molecular beam epitaxy and chemical vapor deposition techniques are presented. The density of the surface states in the high 10(10) eV(-1) cm(-2) near the GaAs midgap for the GaAs grown at 575 and 625 degrees C was obtained. The MIS structure with GaAs homoepitaxial layer grown at 625 degrees C, showing smoother surface morphology than the surface grown at 575 degrees C, exhibited small hysteresis which was as small as 30 mV under a field excursion of 1.5 MV/cm. The presence of a I MHz frequency response at 77 K requires that the traps be within 60 meV of the conduction band edge of GaAs and confirms the unpinned GaAs surface Fermi energy within GaAs band gap. (C) 1996 American Institute of Physics.