Physical and electrical properties of a Si3N4/Si/GaAs metal-insulator-semiconductor structure

We simulated capacitance-voltage (C-V) curves Of Si3N4/GaAs, Si3N4/Si and also Si3N4/Semi* (virtual semiconductor) metal-insulator-semiconductor (MIS) capacitors and compared them with experimental C-V curves of a Si3N4/Si/GaAs structure. The experimental C-V curves of the Si3N4/Si/GaAs MIS capacitors are not in agreement with the simulated C-V curves of the Si3N4/GaAs and Si3N4/Si MIS capacitors, but are in agreement with those of the Si3N4/Semi* MIS capacitors, where Semi* is a virtual semiconductor with n(i)=7x10(11) cm(-3) or EG = 0.88 eV. This indicates that the Si3N4/Si/GaAs structure is somewhat like a narrow band gap material with EG =0.88eV. The comparison yields strong support for our theoretical energy band of the Si3N4/Si/GaAs MIS structure based on quantum well confinement. A depletion mode MIS field-effect-transistor (MISFET) is successfully fabricated with transconductance of 85 mS/mm, and an inversion mode MISFET is fabricated with transconductance of 0.05 mS/mm. The small transconductance for the inversion mode MISFET is ascribed to strong scattering due to confinement of electrons in the Si quantum well. (C) 2001 American Institute of Physics.