| 摘要 |
PURPOSE:To reduce the junction capacitance of the lower section of a gate electrode for a transistor, and to increase the maximum operating frequency of an integrated element by making a semiconductor layer of the lower section of the gate electrode reach a semi-insulating semiconductor substrate. CONSTITUTION:An N type InGaAs layer is formed on a semi-insulating InP substrate 1. A P type diffusion layer 8 reaching to the semi-insulating InP substrate 1 is formed to the lower section of a gate electrode. Since the P type diffusion layer 8 of the lower section of the gate electrode 7 reaches the semi- insulating InP substrate, the junction capacitance of the lower section of the P type diffusion layer 8 is brought to zero, and only the slight junction capacitance of the side surface of the P type diffusion layer 8 remains. |
