Electrical modeling of compound semiconductor interface for FET device assessment

A unified model for GaAs and InP metal-insulator-semiconductor (MIS) systems is presented. It involves particular types of U-shaped distributions of interface states, localized and nonlocalized states, and tunneling processes. Detailed experimental data including the data, frequency dependence of MIS admittance, photocapacitance transient spectroscopy, and deep-level transient spectroscopy, support the model. Formation of a disordered nonstoichiometric semiconductor region is suggested to be the most probable mechanism for the anomalous distributions of interface states. Effects of interface states on microwave MISFET\´s, and implications of the model for logic applications are briefly discussed.