| 摘要 |
PURPOSE:To make it possible to form the gate parts of transistors in both enhancement/depression modes simultaneously and accurately, by selectively removing a semiconductor layer on the surface of a region, where the enhancement type transistor part is to be formed. CONSTITUTION:On a semi-insulating substrate 21, the following parts are grown: a channel layer 22, an electron supplying layer 23, a threshold voltage control layer 24, an etching stopping layer 25, a contact layer 26, an etching stopping layer 27 and a contact layer 28. Etching is performed, and a enhancement type transistor part E and a depression type transistor part D are insulated and isolated. The layers 27 and 28 in the part E are etched and a recess 28A is formed. A contact window is provided. A silicon dioxide film 29 is formed, and electrodes 30, 31, 32 and 33 are formed. Etching is performed, and recesses 35E and 35D are formed. Schottky contact gate electrodes 36 and 37 are formed. The gate electrodes are formed by only one process, and the process can be shortened. |
