Bias-Dependent Trap Characterization in Hydrogen-Terminated Diamond MOSFETs Using Transient Current Analysis

In this study, we investigate the charge trapping in hydrogen-terminated diamond (HD) MOSFETs based on the transient drain current. The hole detrapping is reflected by monitoring the transient current after applying the filling voltages, and three distinct trap peaks are clearly identified using the Bayesian deconvolution. The energy levels are determined from temperature-dependent measurements to be approximately 0.47, 0.35, and 0.15 eV. Besides, the contribution of each trap to the transient current variation can be quantified using the differential amplitude spectra. Three kinds of bias conditions are designed to analyze the dependence of trap amplitudes on filling voltages, which reveals the strong correlation with threshold voltage shift and drain current reduction. By correlating these trap properties with electrical measurements, the physical locations of traps are identified at the interface, in the gate oxide, and in the diamond layer. Notably, the trap within the diamond is found to dominate the current collapse. This work provides profound insights into the trapping mechanisms limiting HD MOSFET performance, establishing a foundation for developing more reliable high-power diamond devices.