| 摘要 |
PURPOSE:To eliminate the need for a deep ion implantation and prevent a short channel effect by performing a recess etching at a part where a gate is expected to be formed after carrying out a highly concentrated n-type ion implantation at source and drain regions and by ion-implantation at an active layer after forming a recessed part. CONSTITUTION:An n<+> type contact layer 5 of around 1X10<18>cm<-3> is formed at a depth of 1,500Angstrom in source and drain regions with an ion implantation technique by using silicon as a dopant and a part where a gate is expected to be formed is etched as a depth of 2,000Angstrom with an etchant having ratios of H2SO4:H2O2:H2O=1:8:600 and a recess 3 is formed. Then, an n-type active layer of around 3X10<17>cm<-3> is formed at a depth of 1,200Angstrom in a recessed part with the ion implantation technique by using photoresists 4 as masks and also silicon as a dopant. After that, if the photoresists are removed, a recess-type GaAs FET having a shallow active layer is completed. This approach not only prevents a short channel effect but also eliminates the need for performing an ion implantation into a deep recess-type active layer.
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