Patent ID: 7310261

Claim:
A nitride read-only memory (NROM) device, comprising: a comparator, having a reference voltage; a bias unit, for outputting a bias voltage to the comparator, wherein the comparator outputs a bit value according to comparison of the bias voltage and the reference voltage, a memory cell, connected to the bias unit via a first switch; a cycling cell, connected to the bias unit via a second switch; a compensation cell, connected to the bias unit via a third switch; and a control unit, for controlling the cycling cell and the compensation cell according to the bit value; wherein in a first stage, the first switch and the third switch turn off, and the second switch turns on, the control unit measures a threshold voltage Vt 1 of the erased cycling cell according to the bit value, and programs a neighbor bit of the cycling cell; in a second stage, the first switch turns off and the second switch and the third switch turn on, the control unit verifies the cycling cell by the voltage Vt 1 and programs the compensation cell with a verify voltage Vt 1 until the bias voltage is substantially equal to the reference voltage; in a third stage, the second switch turns off, and the first switch and the third switch turn on, a read operation is performed on the memory cell and the compensation cell, The memory cell, the cycling cell and the compensation cell are all NROM cells.