| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the effect of short channel effect on fine patterning of memory cell by a structure wherein a second semiconductor layer retains a data corresponding to the impurity concentration thereof and first and third semiconductor layers are connected with voltage applying means, respectively. SOLUTION: The mask ROM is fabricated by forming a first semiconductor layer 4 in a silicon substrate 1 and then forming second and third semiconductor layers 5, 6 thereon to obtain a plurality of memory cells arranged in matrix. The second semiconductor layer 5 is formed by doping a semiconductor layer located immediately above the first semiconductor layer 4 with P type or N type impurities and retains a desired impurity concentration data for each memory cell. The first and third semiconductor layers 4, 6 are connected, respectively, with voltage applying means, i.e., voltage applying circuits connected with a word line 16 and a bit line 10. |
