Channel structure for field effect transistor and method of manufacturing the same.

摘要

This invention provides a high-speed FET with a sufficiently high output current, and an FET having a high mobility of channel electrons and a high electron saturation rate. For this purpose, in this invention, a buffer layer (2), a first channel layer (3), a first spacer layer (4), a second channel layer (5), a second spacer layer (6), a third channel layer (7), and a capping layer (8) are sequentially epitaxially grown on a semi-insulating GaAs semiconductor substrate (1). Drain and source regions (9, 10) are formed, and a gate electrode (11) is formed to Schottky-contact the capping layer (8). Drain and source electrodes (12, 13) are formed to ohmic-contact the drain and source regions (9, 10). Extension of a surface depletion layer from the substrate surface to a deep portion is prevented by the third channel layer (7) closest to the substrate surface. For this reason, a sufficient quantity of electrons for forming a current channel are assured by the second and first channel layers (3, 5). <IMAGE>