Скачать с ютуб Reliability of GaN-power transistors: an overview - G. Meneghesso (Part 2 of 2) в хорошем качестве

Reliability of GaN-power transistors: an overview - G. Meneghesso (Part 2 of 2)

The past few years have been exciting and extremely productive for the GaN community, and the research in the field of GaN-power devices has shown impressive advancements. In lateral GaN HEMTs, a twodimensional electron gas (2DEG) is formed at the interface between GaN and AlGaN; the high mobility of the 2DEG (in excess of 2000 cm2/Vs) results in current densities around 1 A/mm, and in a very low on resistance (25 mΩ for a 650 V/60 A device). This implies a significant reduction in the resistive and switching losses, compared to silicon devices, and this has a positive impact on the efficiency of GaN-based power converters (kW-range power converters with efficiency higher than 99% have already been demonstrated, based on GaN HEMTs). A relevant aspect that is currently under study is the reliability of GaN-based transistors. In fact, during operation in highvoltage power converters, the HEMTs may be subject to extreme field and current levels that may favor device degradation. In real-life applications, several potentially harmful conditions may be reached, favoring the exposure to off-state bias, semi-on stress conditions, hard switching, and high gate bias. This presentation reviews the most recent results published in the field of GaN-based power transistors. After a brief introduction, we discuss the latest technology developments that have an impact on device reliability. Then, we summarize the most important issues related to the degradation of GaN-based HEMTs submitted to stress regimes (off-state, hard switching, positive gate bias, high temperature, ...).