| 摘要 |
PURPOSE:To form a gate electrode along the direction of lamination of a repetitive structure part, and to contrive flattening of the surface of a superlattice element by a method wherein a stepping is formed on the surface of a substrate in advance. CONSTITUTION:A high doping-concentration n<+>GaAs substrate 11 is selectively etched by RIE, and a stepped part 12 is formed. Then, a repetitive structure part 13 is formed by alternately growing undoped GaAs layers 13a, 13c, 13e and AlGaAs layers 13b and 13d on the substrate 11 by a molecular beam epitaxial process, and an n<+>GaAs layer 14 is thickly deposited thereon. Subsequently, a photoresist 15 is coated on the whole surface, and the stepped part is flattened. Then, overall etching is performed until the surface of the substrate 11 is exposed, an undoped AlGaAs layer 16 is formed on the side wall part of the repetitive structure part 13 exposed on the surface of the substrate as a gate insulating film, and a gate electrode 17 is formed thereon. Besides, a source electrode 18 and a drain electrode 19 are formed on both sides of the gate electrode 17. |
