Methods for programming ReRAM devices

摘要

A programming technique for a set of resistance-switching memory cells such as ReRAM cell involves programming the low resistance cells to the high resistance state (in a reset process) early in a programming operation, before programming the high resistance cells to the low resistance state (in a set process), to minimize losses due to leakage currents. The reset process can be performed in one or more phases. In some cases, a current limit is imposed which limits the number of cells which can be reset at the same time. Initially, the cells which are to be reset and set are identified by comparing a logical value of their current resistance state to a logical value of write data. If there is a match, the cell is not programmed. If there is not a match, the cell is programmed.

主权项

1. A method for programming in a memory device, comprising:
for each memory cell of a set of memory cells in the memory device, determining whether the memory cell is in a high resistance state or a low resistance state, wherein each memory cell of the set of memory cells is connected to a common conductive path, each memory cell of the set of memory cells is a resistance change memory cell which is able to change its resistance to store information as a function of its resistance, the set of memory cells is arranged in array and each memory cell is subject to a programming voltage on the common conductive path; identifying from the set of memory cells, a first subset of memory cells, the first subset of memory cells comprises memory cells which are in the low resistance state and which are to be programmed to the high resistance state based on a unit of data; identifying from the set of memory cells, a second subset of memory cells, the second subset of memory cells comprises memory cells which are in the high resistance state and which are to be programmed to the low resistance state based on the unit of data; and responsive to the identifying of the first subset of memory cells and the identifying of the second subset of memory cells: programming the first subset of memory cells before the second subset of memory cells.