| 摘要 |
PURPOSE:To enable to manufacture an integrated circuit device having no rugged surface by selectively forming a GaAs layer on the surface of an N type Al0.3Ga0.7As layer 3, heat treating it, thereby providing an enhancement mode and depletion mode HEMTs. CONSTITUTION:An N type Al0.3Ga0.7As layer 3 is doped with silicon, and a GaAs layer 4 is formed in a thickness of approx. 0.5(mum). The layer 4 on the surface of the region to form an HEMT of an enhancement mode is selectively removed, and holes 6 are opened. Then, a protective film 7 is covered on the surface of the layer 4 containing the surface of the layer 3 exposed in the hole 6, it is then heat treated at the temperature of 700 deg.C or higher. After the film 7 is removed, the remaining GaAs layer 4 is removed, and the surface of the layer 3 is exposed entirely. A gate electrode 8 and source, drain electrodes 9 are selectively formed respectively on the surfaces of the depletion mode element region 3' and the enhancement mode element region 3'' of the layer 3. |
