ELECTRICAL-PROPERTIES OF INPXOY-INP METAL-INSULATOR-SEMICONDUCTOR STRUCTURES

The electrical properties of n-type InP metal-insulator-semiconductor (MIS) structures have been investigated. As gate insulators, InP(x)O(y) layers are formed by a new method. In the method, a P(x')O(y') layer is deposited on InP by evaporation of P2O5 powder. The reaction between the P(x')O(y') layer and InP substrate yields an InP(x)O(y) layers 500-1450 Angstrom thick exhibit high resistivities rho and low dielectric dissipations D, i.e., rho-almost-equal-to 2 x 10(15) OMEGA cm and D less-than-or-equal-to 0.01 in the frequency range 0.02-100 kHz at room temperature. The hysteresis in the capacitance-voltage curves of a typical InP MIS structure is found to be less than 0.6 V and an ion-drift type. The interfacial properties of InP MIS structures are shown to be well explained by the statistical model in the conductance method. A typical value of the minimum surface state density is evaluated as 3.3 x 10(11) cm-2 eV-1 at about 0.26 eV below the conduction-band edge. The distribution of the electron capture cross sections sigma of surface states is also obtained. e.g., sigma = 1.6 x 10(-16) cm2 at 0.4 eV below the conduction-band edge.