| 摘要 |
PURPOSE:To improve the characteristics of a hetero structure field-effect transistor without decreasing an electron mobility by forming an insulating film on the side of a gate pattern, partly etching an electron supply layer, and then growing a single crystal layer made of an N<+> type gallium arsenide to form electrode regions of source and drain to reduce a series resistance between the source electrode and the gate electrode. CONSTITUTION:The entire surface formed with a gate electrode 4 is covered with a plasma nitride film, etched by an RIE unit to form a plasma nitride film 11 on the sidewall of a gate pattern 10. with the pattern 10 and the film 11 as masks an N-type aluminum gallium arsenide layer 3 and a gallium arsenide layer 2 which contains no impurity are partly etched. An N-type gallium arsenide layer 12 which contains an N-type impurity is formed by an epitaxially growing method, an d a polygallium arsenide layer 12 is formed simultaneously on the pattern 10. Thereafter, after a source and a drain are patterned, an ohmic metal is deposited, and lifted off by a resist. It is then heat treated as predetermined to form a source electrode 5 and a drain electrode 6.
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