MANUFACTURE OF HIGH BREAKDOWN VOLTAGE FET

PROBLEM TO BE SOLVED: To generate a high breakdown voltage MESFET in which a strict processing step is saved, by forming a high temperature stable source, a drain ohmic contact and a Schottky gate contact, and making the layer of a passivation material adhere to it. SOLUTION: A gate contact 46 is formed at first and it is used as a mask. The source/drain areas of low resistance are formed in a channel layer 43. A source contact 44 and a drain contact 45 are overlapped against the source/ drain areas in a conductive channel layer 43 and they are formed on the surface of a substrate 41 after annealing. Then, a wafer is completely made into passivation by forming the passivation 50 of a satisfactory dielectric. Thus, a manufacture process is considerably simplified and breakdown voltage can be improved.