| 摘要 |
PURPOSE:To obtain an FET with large freeness in design, high-speed operation, superior high-frequency characteristics and reliability by a method wherein an electron channel is formed on the first layer of three semiconductor layers formed on a substrate, its surface electron density is controlled by the donner density of the second semiconductor layer, and a gate input capacity is controlled by the thickness of the third semiconductor layer. CONSTITUTION:On a semiconductor GaAs substrate 11, high-sensity GaAs semi conductor layer 12, an N-type Al0.3Ca0.7As semiconductor layer 13 which has electron affinity power lower than that of the layer 12, a high-purity Al0.3Ga0.7 As semiconductive layer 14, an ohmic electrodes with AuGe/Ni in the source electrode region 15 and drain electrode region 17, and Al schottky electrode in the gate electrode region 16 are formed. The surface electron density in the electron channel 18 formed on the interface on the layer 12 is controlled by the density of the impurity in the semiconductor layer 13, and the gate input capacity is controlled by the thickness of the semiconductive layer 14, with the result that, for example, a normally-off type FET is easily realized by decreasing the thickness of the layer 13 and density of the impurity. |
