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
${V}_{F} \cdot {Q}_{C}$
to be 144.5
$\text{V}\cdot $
nC (1.53 V
$\times94.3$
nC) 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 (
${I}_{R}$
) of 0.2
$\mu \text{A}$
at 1200 V and maintain an extremely low level of 6.0
$\mu \text{A}$
even at 175 °C, with just 5.8-
$\mu \text{A}$
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 (
${V}_{B}$
) extracted at 50
$\mu \text{A}$
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.