Abstract: A high frequency switch device includes an epitaxy substrate that is formed by sequentially stacking an AlGaAs/GaAs superlattic buffer layer, a first Si planar doping layer, an undoped first AlGaAs spacer, an undoped InGaAs layer, an undoped second AlGaAs spacer, a second Si planar doping layer having a doping density greater than that of the first Si planar doping layer, and an undoped GaAs/AlGaAs capping layer on a GaAs semi-insulated substrate. The undoped GaAs/AlGaAs capping layer is formed with a source electrode and a drain electrode that form an ohmic contact with the undoped GaAs/AlGaAs capping layer thereon, and a gate electrode formed between the source electrode and the drain electrode, thereby forming a Schottky contact with the undoped GaAs/AlGaAs capping layer.

Abstract: A high frequency switch device includes an epitaxy substrate that is formed by sequentially stacking an AlGaAs/GaAs superlattic buffer layer, a first Si planar doping layer, an undoped first AlGaAs spacer, an undoped InGaAs layer, an undoped second AlGaAs spacer, a second Si planar doping layer having a doping density greater than that of the first Si planar doping layer, and an undoped GaAs/AlGaAs capping layer on a GaAs semi-insulated substrate. The undoped GaAs/AlGaAs capping layer is formed with a source electrode and a drain electrode that form an ohmic contact with the undoped GaAs/AlGaAs capping layer thereon, and a gate electrode formed between the source electrode and the drain electrode, thereby forming a Schottky contact with the undoped GaAs/AlGaAs capping layer.

Abstract: A semiconductor device in which a silica aerogel layer having a very low dielectric constant is used as an insulating layer such that parasitic capacitance between a gate electrode and a source electrode in a field effect transistor having a T-shaped gate electrode, and a method of manufacturing the same are provided. The semiconductor device includes a semiconductor substrate, source and drain electrodes, which are formed on the semiconductor substrate to make ohmic contact with the semiconductor substrate, a T-shaped gate electrode, which is formed between the source and drain electrodes on the semiconductor substrate, and an insulating layer including a silica aerogel layer, the silica aerogel layer being interposed between the gate electrode and the source and drain electrodes.