| 摘要 |
PURPOSE:To form an ohmic electrode to an active layer in a self-aligning manner by recess etching the gate of a field effect transistor active layer, and then implanting an impurity having different conductivity type from the active layer only in the recess. CONSTITUTION:An N-type InGaAs layer 2 of one conductivity type active layer, and an InP layer 3 are sequentially grown on an SI-InP substrate 1. Then, the entire substrate is covered with an SiO2 film 4 as a first etching layer, and a gate forming portion is opened. Then, with the layer 4 as a mask a groove 5 which arrives at the layer 2 is formed by etching of bromomethanol. Then, the layer 4 is removed, and a P-type impurity or Cd is diffused in the entire substrate to form a P<+> type layer 6 of other conductivity type layer. Then, the groove 5 is covered by lithography, and an SiO2 layer 7 is formed as a second etching layer at an interval from source, drain electrodes formed in later steps separately from the groove 5. Then, the layer 3 is removed by etching with hydrochloric acid, covered with Au/AuGe of conductive layer to form Au/AuGe layers 8S, 8D, 8G in a self-aligning manner. Thus, a high speed junction FET having small source resistance and gate capacity can be obtained.
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