| 摘要 |
PURPOSE:To ensure high-speed switching and to attain high mutual conductance by a method wherein an overhanging insulating pattern is formed on a gate polycrystalline silicon layer and the length of the overhangs is rendered variable. CONSTITUTION:An Si3N4 film 5C is selectively subjected to photoetching and the surviving Si3N4 film 5C serves as a mask in a process wherein a polycrystalline Si film 6a is subjected to etching for the formation of an overhanging geometry provided with overhangs on both of its sides. P-type ions are implanted into a substrate (n) at an accelerating energy strong enough to drive the ions through the Si3N4 film 5C for the formation of a channel P-layer 4 by diffusion. Patterning is accomplished by means of photoetching, an N type ions are implanted at an accelerating energy not so strong as to drive the ions through the overhangs and a remaining oxide film 5a. Consequently, ions are implanted into regions other than those positioned directly under the overhangs. An SiO2 film 5d is deposited after the formation of a source N<+>-layer 8 by means of diffusion. A contact hole is provided for the formation of an aluminum electrode 9. |
