| 摘要 |
This invention is for improving the radiation hardness or radiation resistance of GaAs MESFETs. According to this invention, an n-type active layer is formed by doping in the GaAs crystal. The n-type active layer includes an upper layer and a heavy doped lower layer. A Schottky gate electrode is provided on the active layer, so that the carrier concentration in the active layer and the thickness of the active layer are set required values. According to this invention, not only in the case of a total dose of exposure radiation of R=1x109 roentgens but also in the case of a higher total dose, at least one of the threshold voltage Vth of the GaAs MESFET, the saturated drain current Idss there of, and the transconductance gm are in their tolerable range. Consequently a semiconductor device comprising the GaAs MESFET and a signal processing circuit cooperatively combined therewith can operate normally as initially designed, with a result of conspicuously improved radiation hardness. |
