Mobility Models Based on Forward Current-Voltage Characteristics of P-type Pseudo-Vertical Diamond Schottky Barrier Diodes

Abstract

Compared with silicon and silicon carbide, diamond has superior material parameters and is therefore suitable for power switching devices. Numerical simulation is important for predicting the electric characteristics of diamond devices before fabrication. Here, we present numerical simulations of p-type diamond pseudo-vertical Schottky barrier diodes using various mobility models. The constant mobility model, based on the parameter μconst, fixed the hole mobility absolutely. The analytic mobility model resulted in temperature- and doping concentration-dependent mobility. An improved model, the Lombard concentration, voltage, and temperature (CVT) mobility model, considered electric field-dependent mobility in addition to temperature and doping concentration. The forward voltage drop at 100 A/cm2 using the analytic and Lombard CVT mobility models was 2.86 and 5.17 V at 300 K, respectively. Finally, we used an empirical mobility model based on experimental results from the literature. We also compared the forward voltage drop and breakdown voltage of the devices, according to variations in p- drift layer thickness and cathode length. The device successfully achieved a low specific on-resistance of 6.8 mΩ∙cm2, a high breakdown voltage of 1190 V, and a high figure-of-merit of 210 MW/cm2.

Effects of incomplete ionization on forward current–voltage characteristics of p-type diamond Schottky barrier diodes based on numerical simulation

“…26) It was discovered that the thickness and doping concentration of the p-drift layer from this study matched with those from the literature. 24) We assumed that m const was 2000 cm 2 V −1 s −1 , and we changed the space between the Schottky and Ohmic contacts, as shown in Fig. 7.…”

“…The simulation results of the diamond Schottky-pn diode, 17) the optimal drift region of the diamond power devices, 21) and the diamond-depleted Schottky pin diode 22) have been reported. We reported the modified impact ionization coefficients 23) and forward current-voltage characteristics with mobility models 24) of p-type pseudo-vertical diamond Schottky barrier diodes. The pseudo-vertical structure is suitable for vertical on-current flows and high breakdown voltages pertaining to the etching process and p-/p+ epitaxial layers on a diamond substrate.…”

“…Fig.7. Simulated specific on-resistance and one24) of p-type diamond pseudo-vertical diamond Schottky barrier diodes from the literature at 300 K. Simulation included incomplete ionization, modified Ohmic contact, and m const of 2000 cm 2 V −1 s −1 .…”