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Gallium Oxide: a new semiconductor candidates for high power electric device

Feng Wu

December 26, 2016 - Posted in Discussion
Gallium oxide has attracted a considerable interest as a functional material for various applications. In these applications, high power high voltage electric device is very appealing because of its high breakdown voltage. The breakdown voltage can reach above 1000 V as shown in the Fig. 1. Besides, it is also attractive from an industrial viewpoint since large-size, high-quality wafers can be manufactured from a single-crystal bulk synthesized by melt–growth methods.
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Recently, there are some reports demonstrating the Ga2O3 based metal semiconductor field-effect transistor (MESFET) and metal oxide semiconductor field-effect transistor (MOSFET), as shown in Fig. 2.
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Fig. 2 Schematic of the Ga2O3 based MESFET and MOSFET
Both of those configurations showed a good device performance, as shown in Fig. 3. The breakdown voltages can reach as high as 370 V. However, right now the Ga2O3 are mostly homoepitaxially grown on bulk Ga2O3 substrate by MBE or HVPE, which is not good for industrial production because of its low yield and high cost. The economic way is to grow this material on sapphire or glass by the mature deposition technique of MOCVD. But the challenge is that the lattice mismatch between Ga2O3 and sapphire or glass is large, which leads to a bad crystal quality of the deposited film on those substrate. However, can we utilize the low temperature buffer layer to improve the crystal quality, just like what researchers did in the GaN growth two decades before? I think this will be very interesting and worthy studying. It will be also very interesting if Ga2O3 can be grown on polymer substrate at low temperature, by pulse laser deposition. Because of polymer substrate, we can fabricate flexible electronic devices which have a potential applications in the future wearable device or flexible display.
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Fig. 3 Dc I–V of the Ga2O3 based MESFET and MOSFET
M. Higashiwaki, K. Sasaki, H. Murakami,Y. Kumagai, A. Koukitu, A. Kuramata, T. Masui, and S. Yamakoshi, “Recent progress in Ga2O3 power devices”, Semicond. Sci. Technol. 31 034001 (2016).
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