| 摘要 |
PURPOSE:To make a capacity created by a diode nearly zero and reduce a noise index by a method wherein a one conductivity type 1st diffused region and the opposite conductivity type 2nd diffused region are provided in a semiconductor substrate and a diode which is composed of the 1st diffused region and the 2nd diffused region is pinched-off at the time of operation. CONSTITUTION:A 1st electrode 5 which is brought into contact with the circumference of 1st diffused region 3 ohmically and 2nd electrode 6 which is contacted with the central region of 2nd diffused region 4 ohmically are provided. The 1st electrode 5 and the 2nd electrode 6 are electrically connected to the source electrode 8 and the gate electrode 9 of a GaAs MESFET 7 respectively. On the other hand, silicon ions Si<+> are implanted into the channel of the GaAs MESFET 7 under the conditions of 3 mu 10<12>cm<-1> and 150 KeV. In this case, when the drain current I0= 10 mA, the gate voltage VGS= -1.5V. In other words, when the semiconductor device is operated, a diode 1 is pinched-off under the condition of VGS= -1.5V. Therefore, a capacity created by the diode 1 becomes nearly zero and a noise index can be improved.
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