| 摘要 |
<p>A multilevel semiconductor EEPROM device characterized by comprising: n-value memory cells (n is 3 or a greater natural number), each having a first threshold voltage to store "1," a second threshold voltage to store "2," a third threshold voltage to store "3," and an i-th threshold voltage to store "i" (i is a natural number equal to or less than n), €ƒ€ƒ€ƒ
wherein during the first programming operation, each memory cell stores "1" in the input data is a first logic level and stores "2" in the input data is a second logic level, and during the kth programming operation, each memory cell stores "A" in the input data is a (2k-1)th logic level and stores "A+2 k-1 " in the input data is a 2kth logic level in the case where the memory cell has been storing "A" during a (k-1)th programming operation (k is 2 or a greater natural number).</p> |
