[16p-4C-1~9] 13.8 化合物及びパワー電子デバイス・プロセス技術

▲ [16p-4C-9] Molecular beam epitaxy of undoped β-Ga₂O₃ (010) for Si-ion-implanted field effect transistors

〇ManHoi Wong¹, Kohei Sasaki^2,1, Akito Kuramata², Shigenobu Yamakoshi², Masataka Higashiwaki¹ (1.NICT, 2.Tamura Corp.)

キーワード：Ga2O3,MBE,Ion implantation

The success of wide-bandgap Ga₂O₃ for future power devices depends critically on high quality epitaxial layers with controllable doping. Molecular beam epitaxy of Sn-doped β-Ga₂O₃ (010) has been restricted to relatively low growth temperatures (T_g) of about 560°C with a narrow window to prevent Sn surface segregation while preserving high crystal quality. The advent of Si ion (Si⁺) implantation for n-type doping lifts the growth constraint imposed by in-situ Sn doping. This work demonstrates that T_g can appreciably influence the resistivity of unintentionally-doped (UID) and the conductivity of Si⁺-implanted Ga₂O₃, thereby highlighting new considerations as well as tradeoffs for achieving device epilayers with optimal structural and electrical properties. The results suggest a T_g window of 620 – 650°C for smooth, resistive UID Ga₂O₃ epilayers and efficient Si⁺ implant activation. Further electrical testing on transistors will establish and validate optimal conditions.