| 摘要 |
PURPOSE:To facilitate formation of two types of FET's in one substrate by a method wherein semiconductor layers of hetero-junction boundaries between semiconductor layers are partially removed and a control electrode is formed on one direct semiconductor layer and a plurality of electrodes which are electronically connected to the partially removed semiconductor layers are provided. CONSTITUTION:An undoped GaAs layer 11 and an undoped AlGaAs layer 14 are made to grow on a semi-insulating GaAs sllbstrate 10. Then an N-type Al GaAs layer 16 and an N-type GaAs layer 17 are made to grow and, after the mesa isolation for isolating between FET elements, an SiO2 film 40 is formed as a protective film of the GaAs surface and a part of the SiO2 film and the N-type GaAs layer 17 are selectively removed and a gate metal 23' is formed. Then, with photoresist 30 as a mask, the SiO2 film 40 is removed and the N-type GaAs layer 17 is removed by dry etching and the N-type AlGaAs layer 16 is selectively removed with potassium iodide solution and chemical washing is performed and, after an E-FET gate metal 23 is formed, source and drain 21 and 22 are formed.
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