Analysis and Characterization of the Punchthrough n-p-n Diode for Hard Switching Power Control Applications

In this article, analysis and characterization of a new punchthrough (PT) n-p-n diode are performed. Numerical analysis shows that the PT voltage
${V}_{{\text {PT}}}$
and the p+ width ratio are the critical parameters to control the hole injection efficiency of the PT n-p-n diode. As a result, a locally reduced carrier profile can be realized due to the existence of electron extraction. Experimental results show that the leakage current of the PT n-p-n diode at 400 K can be kept at a level similar to that of a conventional Self-adjusting P Emitter Efficiency Diode (SPEED) with a well-designed
${V}_{{\text {PT}}}$
. In addition, a p+ width ratio of 20% is optimal for a better peak reverse recovery current (
${I}_{{\text {rrm}}}$
) and forward voltage (
${V}_{{\text {F}}}$
) tradeoff relationship. Compared with SPEED, the PT n-p-n diode achieves a reduced
${I}_{{\text {rrm}}}$
(−21%) and minimized reverse recovery loss
${E}_{{\text {rec}}}$
(−18%) at a nominal current. It can realize a significantly reduced
${I}_{{\text {rrm}}}$
(−42%) even at a small current and a bus voltage of 800 V. Moreover, better reverse recovery performances of the PT n-p-n diode are maintained at 400 K.