III NITRIDE COMPOUND SEMICONDUCTOR ELEMENT AND ELECTRODE FORMING METHOD

摘要

Formed sequentially on a sapphire substrate (1) are a buffer layer (2) of AlN, a high-carrier-concentration n<+> layer (3) of silicon (Si)-doped GaN, an n-clad layer (4) of Si-doped n-Al0.07Ga0.93N, an n-guide layer (5) of Si-doped n-GaN, a multiple-quantum-well-structure (MQW) active layer (6) alternately laminated with well layers (61) of Ga0.9In0.1N each having a film thickness of about 2 nm and barrier layers (62) of Ga0.97In0.03N each having a film thickness of about 4 nm, a p-guide layer (7) of Mg-doped GaN, a p-clad layer (8) of Mg-doped Al0.07Ga0.93N, and a p-contact layer (9) of Mg-doped GaN. A p-electrode (10), reduced in resistance by heat-treating, is formed of titanium nitride (TiN) or tantalum nitride (TaN) having a film thickness of 50 nm.