| 摘要 |
PURPOSE:To improve the write efficiency by enhancing the effect of the implantation of hot electrons by a method wherein the floating gate shape on the drain side is made to have a recess or projection. CONSTITUTION:The hot electrons generated by an avalanche breakdown are accumulated in the floating gate, and then the recess 11 is formed at the angle of theta on the drain side of the floating gate 2 in the semiconductor memory device which memorizes information. A part of the hot electrons generated by the avalanche breakdown is implanted and accumulated in the floating gate 2 by the electric field that a control gate 1 produces in a depletion layer region close to the drain 4. However, since the recess 11 is provided in the floating gate 2 on the drain side, the length of the boundary region wherein the gate and drain contact each is lengthened by the change of the shape of the drain, accordingly the efficiency of electron implantation improves. |
