Al‐Acceptor Incomplete Ionization Effects on Static and Reverse Recovery Characteristics of 4H‐SiC PiN Power Diodes

This work investigates the incomplete ionization effects of aluminum (Al) acceptor dopants on the static and dynamic performance of 4H‐SiC PiN power diodes, using calibrated TCAD simulations. The N dopants form shallow donor energy at E C − 0.065 eV and are nearly completely ionized at room temperature, while the Al acceptor introduces a deeper level at E V + 0.19 eV, resulting in only partial ionization. The reduced acceptor activation decreases the minority carrier injection, thereby undermining conductivity modulation. Hence, 18.4% reduction in forward current at 5 V is observed under the incomplete ionization case, relative to the complete ionization conditions. Conversely, reverse recovery performance improves due to the reduced charge storage under incomplete ionization, leading to 34.2%, 18.9%, and 29.6% reductions in reverse recovery charge ( Q rr ), current ( I prr ), and time ( T rr ), respectively. The reverse I R – V R and C–V characteristics remain unaffected by the incomplete ionization. The Al acceptor energy at E V + 0.02 eV, which yields 99% ionization, is also anticipated at room temperature. Furthermore, the temperature‐dependent ionization behavior of Al acceptors and their influences on the electrical properties are evaluated. Therefore, incomplete Al ionization‐induced deviations in the 4H‐SiC PiN diode properties are comprehensively reported.