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-semicon ductor (MIS) capacitors grown on GaAs(111)B prepared with a combinatio n of in situ molecular beam epitaxy and chemical vapor deposition tech niques 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 presen ce of a I MHz frequency response at 77 K requires that the traps be wi thin 60 meV of the conduction band edge of GaAs and confirms the unpin ned GaAs surface Fermi energy within GaAs band gap. (C) 1996 American Institute of Physics.