Fast System to measure the dynamic on‐resistance of on‐wafer 600 V normally off GaN HEMTs in hard‐switching application conditions

Abstract

This study presents a novel system to investigate the on-wafer level dynamic properties of GaN-based power transistors in hard-switching application conditions. The system is able to analyse devices with an on-resistance (RDSON) in the range from few ohms to hundreds of ohms, and can be effectively used to improve the development process of GaN high electron mobility transistors (HEMTs) power devices at the wafer level. Contrary to the conventional double-pulse setup, where a resistive load is usually used in combination with a very low duty cycle, the dynamic RDSON is acquired during realistic operating conditions, in a boost converter circuit. Consequently, the authors’ system is able to study not only the field-activated trapping processes, but also those induced by hard-switching conditions, i.e. promoted by hot electrons and self-heating. The maximum working voltage (600 V) and the minimum RDSON measurement time after turn-on (2 µs) allow evaluating the operation limit of the devices in a voltage/frequency range close to real switching conditions. Working on the wafer level allows a more realistic assessment of the dynamic RDSON behaviour before the packaging phase, which is very important to improve the production and development process of GaN-HEMT devices.