| 摘要 |
PURPOSE:To obtain a low noise IGFET, by controlling threshold voltage by an ion implantation into a channel and applying the linear voltage with the difference from the gate voltage of approx. 0.2-2V onto a gate electrode. CONSTITUTION:A transistor wherein threshold voltage is controlled by an ion implantation into a channel becomes higher in noise than before the ion implantation. When the ion implantation is performed at 150keV or less, thus the threshold voltage is controlled by setting the net amount of implantation into the channel part in the range of 10<11>-10<13>cm<-2> according to the thickness of a gate insulating film, and the linear electrode with the difference from the gate voltage and the threshold voltage in the range of 0.2-2V is applied onto the gate electrode and used, the noise characteristic approx. the same as before the ion implantation can be obtained, and accordingly it is not controlled by the element dimension or the thickness of a gate insulating film and the kind of implanted ions. |
