| 摘要 |
<p>PURPOSE:To obtain arbitrary output characteristics by a method wherein when a channel region, which is formed between source and drain regions, is covered with oxide films, the thicknesses of the films are partially made to differ from one another, a plurality of threshold values are given to FETs and at the same time, a conductance is given between the sources and drains of the FETs. CONSTITUTION:An N-type source region 1 and an N-type drain region 2 are formed in the surface layer part of a P-type Si substrate, a plurality of oxide films 41 to 46, each having a different thickness, are formed on a P-type channel region 3, which is positioned between these regions 1 and 2, while they are made to head for the region 2 from the region 1 and a common gate electrode 5 is provided on these films 41 and 46. Accordingly, a FET Q1, whose threshold value is VT1 and the value of whose source-drain conductance is gm1, and FETs Q2, Q3, Q4, Q5 and Q6, whose threshold values and the values of whose source-drain conductances are respectively VT2 and gm2, VT3 and gm2, VT3 and gm3, VT4 and gm4, VT5 and gm5 and VT6 and gm6, are obtained and drains, sources and gates of these FETs result in being connected in common. Here, the thicknesses of the films 41 and 46 are properly set and the threshold values are set as the condition of VT1<VT2<VT3<VT4<VT5<VT6.</p> |
