Patent ID: 7826248

Claim:
A write verify method for resistance random access memory (RRAM), the method comprising: applying a reset operation voltage pulse across a RRAM cell, the reset operation voltage pulse changing a resistance of the RRAM cell from a low resistance state to a high resistance state, the high resistance state having a range of resistance values, the reset operation voltage pulse having a first polarity; selecting a lower resistance limit value and an upper resistance limit value, where the lower resistance limit value and the upper resistance limit value are within the range of resistance values and form a narrowed range of resistance values for the high resistance state; applying a forward resetting voltage pulse across the RRAM cell if any of the range of high resistance state resistance values is less than the lower resistance limit value, the forward resetting voltage pulse having the first polarity, repeating the applying one or more forward resetting voltage pulses step until either a predetermined number of pulses is applied or until all of the range of high resistance state resistance values are greater than the lower resistance limit value; and applying a reverse resetting voltage pulse across the RRAM cell if any of the range of high resistance state resistance values is greater than the upper resistance limit value, the reverse resetting voltage pulse having a second polarity being opposite the first polarity, repeating the applying one or more reverse resetting voltage pulses step until either a predetermined number of pulses is applied or until all of the range of high resistance state resistance values are less than the upper resistance limit value.