| 摘要 |
PURPOSE:To obtain a nonvolatile memory enabling writing and erase by a method wherein a source layer is deepened more than a drain layer, and capacity among the layers and a gate electrode is each made unequal. CONSTITUTION:A gate electrode 13 is formed to an SiO2 film 12 on a semiconductor substrate 11, P ions are selectively injected to make up an N layer 15, As is deposited on the layer 15 and a layer 14, and the whole is thermally treated. Width xj2 and xj1 can be formed in value such as xj2 0.3mum, xj1 2mum by the difference of the speed of diffusion of P and As, channel length is shortened only by (0.3+ 2)mum to the length of the gate electrode, and gm is increased. Capacity CGS is about septuple as great as CGD because the quantitites of overlap among the gate electrode and both the source layer 15 and the drain layer 14 are each 2mum and 0.3mum. In an ROM electrically erasing, this constitution can improve the efficiency of writing and erase, shortens effective channel length, ameliorates gm and results in no trouble in a degree of integration. |
