| 摘要 |
PROBLEM TO BE SOLVED: To provide an ohmic electrode and its forming method which has a low contact resistivity with an n-type nitrogen III-V compound semiconductor. SOLUTION: When an ohmic electrode is formed on an n-type GaN layer 1 having a low carrier density, after forming an Al-Si alloy film or an Al/Si multi-layer film 2 on the n-type GaN layer 1, n<+> -type layer 3 having a high carrier density is formed by diffusing Si in the Al-Si alloy film or the Al/Si multi-layer film 2 into the n-type GaN layer 1 by means of thermal processing at temperature of 500 to 600 deg.C. An Au-Si alloy film or an Au/Si multi-layer film may be used instead of the Al-Si alloy film or the Al/Si multi-layer film 2. When the ohmic electrode is formed on an n-type GaN layer having a high carrier density, after forming a Ti film, an Al film, a Pt film and an Au film in order on the n-type GaN layer, thermal processing at temperature of 700 to 1,100 deg.C is performed. |
