| abstract |
PURPOSE:To utilize Al wirings as part of an ion implantation mask for forming ROM eyes by a method wherein the titled device is so constructed that part of the Al wiring is overhung to cover at least one region of a source and a drain. CONSTITUTION:A P type well 12 is formed on an N type Si substrate 11, and a field oxide film 13 almost of square form is arranged by alienation on its main surface; then, a gate oxide film 14 is formed therebetween. A gate electrode 15 is formed thereon, and the P type well 12 is doped with an N type impurity of As or P by utilizing this electrode, resulting in the formation of source and drain regions 16 and 17. Next, Al wirings 20 and 21 as data lines are extended in the direction of intersection with the gate electrode 15. Thus, an MOSFET can be constructed. In the case of forming a ROM eye using an MOSFET as the memory, since the whole area of the drain region 17 is covered with the Al wiring 21, this wiring serves as part of the mask even by boron implantation. |