Determination of Heterojunction Energy Band Discontinuities in the Presence of Interface States Using Capacitance-Voltage Techniques

摘要

Effects of trapped interface charge on the determination of heterojunction energy band discontinuity energies using capacitance-voltage (C-V) techniques are analyzed both theoretically and experimentally. We show that for shallow traps, whose charge occupancy is unchanged by variations in the applied voltage, the measured conduction band discontinuity energy as determined by the depletion technique (Kroemer, Chien, Harris, and Edwall, Appl. Phys Lett. 36, 295 (1980)) is a function of trap density. This error source in determining is large for small values due to distortions of the conduction band induced by the trapped interface charge. Reprints. (rh)