| 摘要 |
PURPOSE:To reduce a gate resistance without increasing the thickness of a gate metal film by selectively growing W by means for reacting gas containing W with Si formed on a gate electrode forming portion to form a gate electrode. CONSTITUTION:The channel layer 2 of FET is formed by implanting impurity ions into a GaAs semi-insulating substrate 1, an insulating film 3 is formed, with a resist 4 as a mask the gate forming portion of the film 3 is etched to form a hole 5. A polysilicon 6 is formed in the hole 5, the polysilicon 6 is re placed with a W metal film 7 by utilizing the reaction of WF6 with Si, H2 gas having reduction of WF6 gas is, for example, fed to seed the film 7, thereby forming the W metal film also on part on the film 3. After the film 3 is re moved, with the film 7 as mask for ion implanting to ion implant and anneal a contacting layer 8, thereby forming an ohmic metal layer 9 on the layer 8.
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