| 摘要 |
PURPOSE:To write date into a mask ROM by subjecting a ROM structure to H<+> ion implantation and heat treatment before it is furnished with a passivation film. CONSTITUTION:FETs, which are not to be connected with bit lines, are selected out of all the FETs in a mask ROM according to a user program. Hydrogen ions are introduced to the doped channel regions 12 of the selected FETs. The doped channel regions 30 are then heat-treated (28). This heat treatment is carried out to combine the hydrogen atoms, the silicon atoms in a substrate 10, and the dopant atoms in the doped channel regions 30 to make the dopant atoms inactive. |
