| 摘要 |
<p>A transistor of MIS type multigate structure is used in a ROM (read only memory) by disposing a threshold voltage controlling region under each gate and making use of the difference in the threshold voltage at the gates. The threshold voltage controlling region of one of the gate structures in such multigate structure is obtained by etching the semiconductor substrate (11), using the first gate structural part (14, 15) as the mask, to form a specified impurity diffusion layer (18) in the etched surface and by forming a second gate structural part (19, 20) thereon. Said first and second gate structural parts may be formed by self-matching method, and their positioning may be easy, so that the response to downsizing of parts may be improved, and a structure suited to higher degree of integration will be realized.</p> |
