T. T. Pham

Metal oxide semiconductor capacitors were fabricated using $p-$ type oxygen-terminated (001) diamond and Al₂O₃ deposited by atomic layer deposition at two different temperatures 250 °C and 380 °C. Current voltage I(V), capacitance voltage C(V), and capacitance frequency C(f) measurements were performed and analyzed for frequencies ranging from 1 Hz to 1 MHz and temperatures from 160 K to 360 K. A complete model for the Metal-Oxide-Semiconductor Capacitors electrostatics, leakage current mechanisms through the oxide into the semiconductor and small a.c. signal equivalent circuit of the device is proposed and discussed. Interface states densities are then evaluated in the range of ${10}^{12}{\text{eV}}^{-1}{\text{cm}}^{-2}$ . The strong Fermi level pinning is demonstrated to be induced by the combined effects of the leakage current through the oxide and the presence of diamond/oxide interface states.

A stable deep depletion regime is demonstrated in metal oxide semiconductor capacitors using $p$ -type oxygen-terminated (100) diamond as a semiconductor and Al₂O₃ deposited by Atomic Layer Deposition at 380 °C. Current voltage I(V) and capacitance voltage C(V) measurements were performed to evaluate the effectiveness of diamond semiconductor gate control. An effective modulation of the space charge region width is obtained by the gate bias, where the deep depletion regime is demonstrated for a positive gate bias. The deep depletion concept is described and proposed for MOSFET devices. Finally, a proof of concept of diamond deep depletion MOSFETs is presented.