Investigation of α-SiC p+/n/n+ diode temperature-voltage and breakdown characteristics

Given the growing demand for high-power, high-temperature semiconductor devices in fields such as new energy and aerospace technology, traditional silicon (Si) diodes cannot meet the requirements of extreme operating conditions due to their narrow bandgap limitations. α-SiC (6H-SiC), with its wide bandgap (3.0 eV) and high breakdown strength (2.5 MV/cm), is emerging as an ideal material for high-temperature, high-power equipment. However, further research is needed on its high-temperature carrier transport mechanisms, collision ionization processes, and the application of relevant simulation tools. This study employed Silvaco Atlas software to create an α-SiC p+/n/n+ vertical diode model. Quasi-3D simulations were conducted using a cylindrically symmetric grid, precisely delineating the p+ emitter region (high p-type doping), n-base region (low n-type doping), and n+ emitter region (high n-type doping). Material parameters such as dielectric constants and carrier mobilities were determined by activating the electric field migration model, SRH recombination model, Auger recombination model, and bandgap narrowing model. Direct I-V characteristics were simulated over an anode bias range of 0.2–4.0 V at both 300 K (room temperature) and 623 K (high temperature). At 623 K, reverse characteristics were simulated by scanning reverse voltage until a current of 1×10⁻⁹ A was reached, with visualization analysis performed using TonyPlot. Results indicate that for reverse current characteristics, leakage current at 623 K remains stable within the range of-100 V to-700 V (10⁻¹²-10⁻¹³ A). Above-700 V, avalanche breakdown occurs due to the electric field concentration in the n-type base region.