Degradation Mechanisms of Hydrogen-Terminated Diamond MISFETs Under Off-State Stress Conditions

This article investigates the degradation mechanisms of hydrogen-terminated (C-H) diamond metal-insulator-semiconductor field-effect transistors (MISFETs) submitted to OFF-state stress. Both pulsed characterization and transient ON-resistance ( R-ON ) measurements are used. For the pulsed characterization, R-ON increases with the increased intensity of the drain quiescent bias. However, the threshold voltage ( V-TH ) increased (i.e., carrier concentration increase) with the increased intensity of the drain quiescent bias, which is different from the GaN-based devices that carrier concentration decreased with the increased intensity of the drain quiescent bias due to the trapping effects under the gate region. By means of various pulse periods (PPs) and gate quiescent biases, demonstrating that an increase in V-TH is mainly due to the detrapping effects under the gate region, an increase in R-ON is primarily due to the trapping effects in the gate-drain access region. Based on the results of transient R-ON measurements, two kinds of traps with different activation energies (0.28 and 0.24 eV) are determined. These results are helpful to improve the performance of C-H diamond MISFETs.