| 摘要 |
<p>A semiconductor memory comprises a p⁻-type semiconductor substrate (1), a p-type epitaxial layer (15) and p⁺-type epitaxial layers (16, 17) formed thereon, an n⁺-type region (6) formed on the p⁺-type epitaxial layer (16) to serve as a bit line, an n⁺-type region (5) formed on the p⁺-type epitaxial layer (17) to serve as a charge storage region and a gate electrode (9) formed on the p-type epitaxial layer (15) to serve as a word line. The p⁺-type epitaxial layers (16, 17) prevent passage of electrons within electron-hole pairs induced by alpha rays, to suppress occurrence of soft errors. The p-type epitaxial layer (15) defines a region corresponding to the channel region of a bus transistor, whereby the impurity concentration thereof can be easily controlled, to readily set the threshold voltage of the bus transistor at an appropriate level. </p> |
