1.2-kV 4H-SiC JBS Diodes Engaging P-Type Retrograde Implants

In this article, we propose the use of p-type retrograde implants (RPs) for enhanced device performance and alleviated temperature dependence of leakage current in 4H-SiC junction barrier Schottky (JBS) diodes. Two 1200-V JBS diodes consisting of optimized RP have been designed, fabricated, and characterized. The RP offers the following merits for JBS: 1) deeper p-n junction to reduce electric field at the Schottky interface; 2) more width of the space charge zone to decrease capacitance; 3) more depletion region in the p-type unit to partly undertake blocking voltage; and 4) higher doping of subsurface region to address the reach-through issue. The fabricated RP devices yielded a remarkable enhancement of an ultralow VF · QC to be 144.5 V · nC (1.53 V ×94.3nC) at 20-A rated current, which might be the reported lowest one to the best of our knowledge. What is more, the RP-JBS diodes could realize a leakage current IR of 0.2 μ A at 1200 V and maintain an extremely low level of 6.0 μ A even at 175 °C, with just 5.8- μ A increasement over the temperature range of -50 °C to 175 °C. Compared with the latest commercial JBS products from leading companies, the RP-JBS diode has shown its significant capability of mitigating the impact of rising temperatures on device performance. In particular, only 8.4% roll-off of breakdown voltage VB extracted at 50 μ A was obtained. The superior performance of the 4H-SiC JBS diodes with RP makes the device a promising candidate for high-temperature, high-voltage, and high-frequency applications.