| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to manufacture a bit transistor of a smaller geometric shape without using an advanced costly lithographic tool. SOLUTION: The strip of a semiconductor material (e.g. P-type silicon) is oxidized, and the strip of oxide obtained as a result is removed. Then, depressions are left on the upper frontal surface of the semiconductor material having a sidewall of steep slope. There is no significant damage by ion bombardment on the sidewall of steep slope. It is because these are formed by oxidation and not by performing reactive ion etching on the semiconductor material. Therefore, a high-quality tunnel oxide can be formed on the sidewall of steep slope. Next, a floating gate 124 is formed on the tunnel oxide, and the corresponding word line is formed on the floating gate. After that, a conductive region (e.g. N-type silicon) is formed inside the bottom of the depressions. Finally, several conductive regions 150 (e.g. N-type silicon) corresponding to the floating gate are formed at the upper part of the edge of the depressions. COPYRIGHT: (C)2006,JPO&NCIPI
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