Patent ID: 7968430

Claim:
A compound semiconductor device comprising a laminated body including a crystal substrate and a compound semiconductor multilayer film, the laminated body having a major surface, a first side face, a second side face, a third side face, and a fourth side face, the first and the second side faces being opposed to each other, the first and the second side faces being substantially perpendicular to the major surface of the laminated body, and the first and second side faces being made of cleaved surfaces, the third and fourth side faces being perpendicular to the major surface and to the first and second side faces, the third and fourth side faces being opposed to each other, and the third and fourth side faces being made of uncleaved surfaces, a groove being provided on the third side face, the groove extending from the major surface and having a depth varied with position as viewed from the major surface, and the groove having ends not reaching the first and second side faces, a spacing between one end of the groove and the first side face being smaller than a spacing between the other end of the groove and the second side surface, and the depth of the groove at the one end closer to the first side face being smaller than the depth of the groove at the other end closer to the second side face.