On the suitability of Gallium-Nitride (GaN) based automotive power electronics

Abstract

Abstract─This paper aims at discussing the possibility of using GaN power devices in automotive power electronics applications. The major issues with current silicon-based devices are highlighted in this paper. Furthermore, the paper also discusses the possible solutions offered by wide-band gap semiconductors, specifically Gallium-Nitride (GaN). The fundamental steps in designing GaN devices includes choosing the substrate, the dimensions of each layer, the length of gate, drain, source, and the distance between them, selecting materials for contacts, and finally, optimizing passivation layer. Moreover, to achieve higher breakdown voltages, field plate technology has to be executed. High voltage, high current, and high temperature operation of previously fabricated GaN devices are studied and summarized. It can be concluded that GaN definitely has the potential to dominate the next generation of automotive power electronic systems. However, certain issues, such as normally-off and vertical operation have to be thoroughly elucidated.

Merits of gallium nitride based power conversion

“…Exploration of GaN's ability to operate under extreme conditions is still in its early stages [8]. However, one area that GaN could make significant contributions is in high temperature power electronics [5,6]. The automotive industry is particularly interested in this application.…”

“…The automotive industry is particularly interested in this application. A high temperature inverter could eliminate the auxiliary cooling system used for the electronics and rely on the same hardware used to cool the internal combustion engine [5,6].…”

“…As a result, the size of hardware has been reduced and the efficiency of these systems has greatly improved. However, many in the power electronics community feel that Si devices cannot meet the future needs expected from power electronics hardware [1][2][3][4][5][6][7]. This is the result of market demands for further improvements in efficiency, additional reduction in physical sizes, and the ability to operate at higher temperatures so that equipment can be developed for everything from consumer goods to military applications.…”

“…However, GaN has several hurdles that must be overcome prior to gaining widespread acceptance in industry. Possibly the most significant challenge is achieving a higher threshold voltage for normally-off devices [2,[4][5][6]8]. Limiting gate leakage current is necessary to achieve higher breakdown voltages [2].…”

“…Also being explored is the use of SiO 2 to both realize a MOSHEMT structure and act as passivation [14,17]. Additionally, it is felt that a vertical structure will open the door to high current, high power applications, but this will require the production of high quality, free standing GaN substrates [6,8].…”