Verify scheme for ReRAM

摘要

Circuitry coupled to a programmable element comprising metal oxide is configured to execute a program-verify operation including: an initial cycle of a program operation and a verify operation, and subsequent cycles. The initial cycle includes an initial instance of the program operation to establish a cell resistance of the programmable element, and an initial instance of the verify operation to determine whether the cell resistance of the memory cell is within the target resistance range. At least one of the subsequent cycles includes an additional pulse having a second polarity to the programmable element, and a subsequent instance of the verify operation. The first polarity of the initial program pulse and the second polarity of the additional pulse have opposite polarities. A subsequent instance of the program operation includes applying a subsequent program pulse having the first polarity to the programmable element.

主权项

1. An integrated circuit, comprising:
a programmable element comprising metal oxide; and circuitry coupled to the programmable element, the circuitry configured to execute a program-verify operation including:
(i) an initial program-verify cycle including:
applying an initial program pulse having a first polarity to the programmable element to establish a cell resistance of the programmable element; and thendetermining whether the cell resistance of the programmable element is within a target resistance range; and then(ii) subsequent program-verify cycles performed if the cell resistance of the programmable element is not within the target resistance range, iterated until the cell resistance of the programmable element is within the target resistance range,wherein at least one of the subsequent program-verify cycles to establish the cell resistance of the programmable element within the target range includes:
applying an opposite polarity pulse having a second polarity to the programmable element, the first polarity and the second polarity having opposite polarities; andapplying a subsequent program pulse having the first polarity to the programmable element; and thendetermining whether the cell resistance of the programmable element is within the target resistance range.