| 摘要 |
<p>PROBLEM TO BE SOLVED: To increase an ION/IOFF ratio, by covering a gate electrode with an insulator, and constituting a semiconductor layer to which an impurity to become a doner or acceptor is added separately at a distance shorter than a thickness of the insulator. SOLUTION: After a gate electrode 105 made of tantalum is formed with the electrode 105 used as a mask, phosphorus ion is, for example, implanted in a polycrystal silicon in a self-alignment manner through a gate insulating film 107 to form a source region 104 and a drain region 103. Then, an insulator 106 formed of tantalum oxide is formed on a surface with the electrode 105 made of the tantalum by using an anodizing method. As a result, an offset amountΔL is brought about. The amountΔL can be accurately controlled by an anodizing voltage. Thus, since the amountΔL exists, a voltage between the gate electrode and the drain region or between the gate voltage and the source region when a gate voltage Vgs is set negative, can be effectively lowered.</p> |
