Berlin 2015 – scientific programme

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DS: Fachverband Dünne Schichten

DS 34: Focussed Session: Oxide semiconductors I (joint session with HL)

DS 34.1: Invited Talk

Thursday, March 19, 2015, 09:30–10:00, H 2032

Growth, properties and devices of gallium-oxide-based widegap semiconductors — •Shizuo Fujuta — Kyoto University, Kyoto, Japan

Recently, high-power devices with orthorhombic α-Ga₂O₃ have attracted increasing interest supported by solution-grown highly-crystalline substrates. However, orthorhombic crystals are rare in semiconductor family, hence there hardly are other semiconductors of the same crystal structure for alloys or multilayer structures with α-Ga₂O₃. On the other hand we have developed the growth of corundum-structured α-Al₂O₃, α-Ga₂O₃, α-In₂O₃ and their alloys achieving the band gap engineering from 3.8 to 8.8 eV, overcoming metastable phases of α-Ga₂O₃ and α-In₂O₃. For the growth we can apply a low-cost and environmental-friendly mist CVD method, which allowed highly-crystalline films as evidenced by FWHM of ω-scan XRD curves as small as <50 arcsec for α-Ga₂O₃ and <500 arcsec for others. The author will report crystal qualities, electrical properties, doping and preliminary device performances with MOS structures at the conference. In addition, alloying with transition-metal oxides such as α-Fe₂O₃ or α-Cr₂O₃ achieves addition of magnetic properties to semiconductors, as evidenced by magnetization hysteresis at >300K. This can also develop new multifunctional materials and devices with function engineering.