Low-temperature direct bonding of beta-Ga2O3/diamond for advanced power electronics

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K15044
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 26030:Composite materials and interfaces-related
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Matsumae Takashi 国立研究開発法人産業技術総合研究所, エレクトロニクス・製造領域, 研究員 (10807431)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Keywords: 酸化ガリウム / ダイヤモンド / 直接接合 / 放熱構造 / pnジャンクション

Outline of Final Research Achievements

Gallium Oxide (Ga2O3) is regarded as a future power electronics material but has a low thermal conductivity. For the efficient heat dissipation for the Ga2O3 power device, we have developed the direct bonding technique between Ga2O3 and diamond substrates. The thickness of the amorphous layer at the Ga2O3/diamond interface was less than 1 nm. The thermal resistance of the Ga2O3/diamond hetero-structure was reduced than the conventional Ga2O3 substrate. In addition, the rectification property was demonstrated by using the direct bonded n-Ga2O3/p-diamond interface.

Free Research Field

表面・界面

Academic Significance and Societal Importance of the Research Achievements

今回実施が容易という特徴をもつ大気中での直接接合を採用した。Siなどの既存の半導体材料の直接接合では接合界面に酸化物の障壁層ができていたが、酸化物である酸化ガリウムと、表面酸化層ができないダイヤモンドの間では上記障壁層が数原子レベルまで抑制できることが分かった。これにより酸化ガリウムからなるパワー半導体からダイヤモンド放熱基板への理想的な放熱が期待され、新しい省エネデバイスの実現が期待できる。