Dynamics of hole injection from p-GaN drain of a hybrid drain embedded GIT

Abstract

The addition of a p-GaN drain to a conventional gate-injection transistor (GIT), forming the so-called hybrid drain embedded GIT, is crucial in the suppression of the dynamic Rdson. The DC leakage due to hole injection is limited to around 10 nA/mm at 600 V (25 °C). However, an injected hole current of several amperes (W = 210 mm) has been observed during the hard switching event. To reconcile this difference over 6 orders of magnitude, a TCAD study is carried out to understand the dynamics of the hole injection and what leads to the difference between the static and the transient current. According to the scenario played out by the present simulation model, the high concentration of carbon, intentionally doped to control the vertical leakage, plays a crucial role in limiting the hole injection current to its DC level, while under fast switching, the hole injection current can be very high due to a lag in response on the part of the carbon trap.