| 摘要 |
PURPOSE:To obtain GaAs elements, whose characteristics are uniform, with good reproducibility, by making it possible to perform substrate heating, with an inorganic insulating film as a mask at the time of the formation of a gate. CONSTITUTION:On a semi-insulating GaAs substrate 30, an N type GaAs active operating layer 31 is grown. An SiN film 32 is formed thereon. Source- and drain-electrode forming parts 33 and 34 are formed thereon. Patterning of a photoresist layer 36 is performed so that an interval of about 2mum is provided between a gate-electrode forming part 35 and the parts 33 and 34. The operating layer 31 is exposed by etching. The electrode forming part 35 is selectively coated by a photoresist layer 37. Then, the SiN film 32 is etched by a buffer HF. A metal for forming the operating layer 31 and an ohmic contact is evaporated. The photoresist layers 36 and 37 are removed, and a source electrode 39 and a drain electrode 40 are formed. Then the operating layer 31 is dug until a specified pinch OFF voltage is obtained. Thereafter, a gate electrode 421 is formed in a self-aligning manner with respect to the source and drain electrodes 39 and 40 in a recess part.
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