Capacitance-voltage behavior of insulated gate InGaAs HEMT capacitors having silicon interface control layer

Basic insulated gate HEMT (IGHEMT) capacitors with and without a Si interface control layer (ICL) were fabricated, and their capacitance-voltage ( C - V ) characteristics were compared in detail (10 3 –10 9 Hz, 50 K–300 K). The basic IGHEMT capacitors with Si-ICL were found to exhibit an unexpectedly large frequency dispersion of capacitance. By performing detailed low-temperature measurements, it was found that the observed frequency dispersion of capacitance was due not to the interface states but to the rate limitation of the carrier supply, and the nearly ideal nature of an IGHEMT capacitor with Si-ICL was confirmed.