| 摘要 |
PURPOSE:To avoid disconnection of a gate electrode formed later in a semiconductor device by forming a semiconductor layer on an insulating substrate, altering a field to an insulating layer, forming a gate electrode and its extension from the semiconductor layer becoming an island state to the insulating layer, and removing the insulating layer disposed except the gate electrode and its extension. CONSTITUTION:An Si layer 25 is epitaxially grown as a semiconductor layer on a sapphire substrate 21, is thermally oxidized to alter only the surface layer into an SiO2 film 22, and an Si3N4 film 23 is coated on the entire surface thereof. Then, the laminated films of a field portion are etched to reduce the thickness thereof, are then heat treated to expand its volume, and an Si layer 25 is surrounded in an island state by the thick field SiO2 film 24 thus produced. Thereafter, both films 23 and 22 are removed, are again heat treated, a gate SiO2 film 26 is formed thereat, and a polycrystalline Si gate electrode 27 made of an electrode and a wire extension connected thereto is formed thereon. Subsequently, the film 26 is retained only under the electrode 27, other film 26 is removed, source and drain regions 30 and 31 are diffused and formed in the exposed region 25 at both sides of the electrode 27, and aluminum electrodes 33 and 34 are coated thereon. |
