Advancing Metal-Oxide-Semiconductor Theory: Steady-State Nonequilibrium Conditions

This article investigates steady-state nonequilibrium conditions in metal-oxide-semiconductor (MOS) capacitors. Steady-state nonequilibrium conditions are of significant interest due to the advent of wide-gap semiconductors in the arena of MS (or metal-insulator-semiconductor) devices and due to the scaling of oxide thickness in Si technology. Two major classes of steady-state nonequilibrium conditions were studied both experimentally and theoretically: (i) steady-state deep depletion and (ii) steady-state low level optical generation. It is found that the identification and subsequent understanding of steady-state nonequilibrium conditions is of significant importance for correct interpretation of electrical measurements such as capacitance-voltage and conductance-voltage measurements, Basic implications of steady-state nonequilibrium conditions were derived for both MOS capacitors with low interfaces state density Di, and for oxide semiconductor interfaces with a pinned Fermi level. Further, a photoluminescence power spectroscopy technique is investigated as a complementary tool for direct-gap semiconductors to study Di, and to monitor the interface quality during device fabrication. (C) 1997 American Institute of Physics.