| 摘要 |
PURPOSE:To obtain a memory of high integration that can store 2 bits by one cell by programming the length of channel of a cell transistor and compensating scattering of a threshold voltage due to process fluctuation. CONSTITUTION:Four patterns of a cell 40 that does not form a transistor and cells 41-43 that make channel length L1-L3 are programmed. When selection voltage Vcc is applied to a selection line 102, voltage of an output line 400 does not change, and voltage Vcc-V1, Vcc-v2, Vcc-V3 that depends on threshold values V1-V3 is outputted to output lines 401-403. Accordingly, it is possible to compare four values of the cell output line 400 by a comparator and output binary signal corresponding to combination of output of the comparator. Even when output is deviated due to deviation of channel length from L1-L3, scattering of the channel length due to processing can be compensated as comparative voltage of the comparator changes. |
