COMPOUND SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

PROBLEM TO BE SOLVED: To provide a compound semiconductor device including an ohmic electrode with a high reliability and a manufacturing method of the compound semiconductor device.SOLUTION: The compound semiconductor device includes a nitride semiconductor layer and an ohmic electrode formed on the nitride semiconductor layer. In the compound semiconductor device, the ohmic electrode includes a first electrode layer containing a metal forming a metallic nitride between the first electrode layer and the nitride semiconductor layer and a second electrode layer formed on the first electrode layer and containing aluminum (Al). In the compound semiconductor device, the ohmic electrode further includes a third electrode layer coating the external surface of the second electrode layer and containing tungsten (W) and a fourth electrode layer coating the external surface of the third electrode layer and containing gold (Au).