Depletion and enhancement mode β-Ga&lt;inf&gt;2&lt;/inf&gt;O&lt;inf&gt;3&lt;/inf&gt; MOSFETs with ALD SiO&lt;inf&gt;2&lt;/inf&gt; gate and near 400 V breakdown voltage

Ke Zeng,T Masui,Uttam Singisetti,A Kuramata,K Sasaki

doi:10.1109/drc.2016.7548430

Abstract

As a next generation wide bandgap semiconductor for power electronics, β-Ga 2 O 3 (Ga 2 O 3 ) has shown a lot of potential in recent studies. It has been reported to have high Baliga's Figure of Merit (BFoM), a figure of merit for power devices, next only to diamond among wide bandgap semiconductor materials [1]. Moreover, a mature growth technology for large area substrates is a major practical advantage for cost effectiveness and rapid adaptation by industry [2]. Because of the advantages of this material, depletion mode MOSFETs and Schottky diodes based on Ga 2 O 3 with high breakdown voltages have been recently demonstrated [3][4]. However, enhancement mode MOSFETs are preferred in power electronics applications. All the previous work incorporated ALD Al 2 O 3 as gate barrier due to its high dielectric constant. However, a recent study reported that SiO 2 /Ga 2 O 3 interface has a much bigger conduction band offset than that of Al 2 O 3 /Ga 2 O 3 [5] which is preferred in MOSFET. In addition, SiO 2 /Ga 2 O 3 interface has a relatively low interface states density according to our recent data. These properties make SiO 2 an attractive gate dielectric for Ga 2 O 3 power MOSFETs. Here, we first report depletion mode MOSFET on MBE grown Ga 2 O 3 with an ALD SiO 2 gate. We also report the first successful enhancement mode MOSFET on β-Ga 2 O 3 . Both depletion mode and enhancement mode MOSFETs show near 400 V off state drain source breakdown voltage.

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