| 摘要 |
An electrical contact (130, 230, 330, 430) that comprises a layer (118) of a p-type gallium nitride material, a metal layer (134), and a intermediate layer (132, 232, 332, 432) of a material different from the gallium nitride material and the metal layer. The intermediate layer is sandwiched between the layer of p-type gallium nitride material and the metal layer. The material of the intermediate layer (132) may be a Group III-V semiconductor that has high band-gap energy, lower than that of the p-type gallium nitride material. The intermediate layer (232) may alternatively include layers (e.g., 240, 242, 244) of different Group III-V semiconductors. The layers of the different Group III-V semiconductors are arranged in order of their band-gap energies, with the Group III-V semiconductor having the highest band-gap energy next to the layer of the p-type gallium nitride material, and the Group III-V semiconductor having the lowest bad-gap energy next to the metal layer. As a further alternative, the material of the intermediate layer (332) may be a metal nitride. As a yet further alternative, the material of the intermediate layer (432) may be a gallium nitride material in which a percentage of the nitrogen atoms are replaced by a mole fraction x of atoms of at least one other Group V element. The value of x is close to zero next to the layer (118) of p-type gallium nitride material, and is substantially greater than zero next to the metal layer (134). <IMAGE> |
