Performance and reliability of commercial GaN-on-Si power devices

  • Samuel Perkins

Student thesis: Master's ThesisMaster of Science by Research

Abstract

Commercial GaN-on-Si based power devices are now available up to the 650 V class. Theoretically GaN-on-Si power devices offer extremely high performance capabilities and relatively low production costs. The unique material properties of GaN have attracted a lot of attention from the power electronic sector within the past 20 years. The combination of high thermal conductivity, critical electric field, wide bandgap, high electron saturation and the plateau of traditional Silicon technology has motivated this interest. However, the development of commercial GaN-on-Si device has been shrouded in complex and extensive challenges. Normally-on operation, current collapse and high levels of crystal defects are to name but a few. Furthermore, Silicon Super-junction technology has recently seen rapid progression in their performance and production costs. This has indirectly slowed the adoption of GaN-on-Si power devices.

The direction of GaN-on-Si based power HEMT devices is split among manufactures. Panasonic, GaNsystems and EPC have adopted GaN-on-Si GIT Enhancement mode devices. Whereas; Transphorm has pioneered the cascode GaN-on-Si HEMT. Both GaN-on-Si technologies have been developed for similar voltage and current classes. As the technologies are significantly different it is logical to assume that the performance of these devices will be.

In this thesis, naturally Enhancement mode and cascode GaN-on-GIT enhancement mode GaN-on-Si power devices are characterised in terms of their static characteristics at room temperature and at their maximum rated temperatures. The experimental result of this characterisation shows the immense difference between the different behaviour of the two different GaN-on-Si power devices. Therefore, systems designers need to consider the differences before device choice.

Date of AwardFeb 2018
Original languageEnglish
Awarding Institution
  • Coventry University
SupervisorNeo Lophitis (Supervisor)

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