Phase change memory (PCM) is an emerging, resistance-based, nonvolatile memory. With a promising scaling potential, PCM can replace the existing charge-based memory technologies. A highly scaled PCM is prone to write disturbance (WD) because of a high-current RESET programming pulse. Exploiting the data-dependent nature of WD, encoding techniques have been proposed to reduce the frequency of WD-vulnerable data patterns. These techniques work along with a verify and correct (VnC) method to ensure memory reliability. However, the effectiveness of these techniques varies depending on the data patterns. Unlike the conventional methods, this article introduces a WD-aware programming technique to mitigate WD in PCM. The proposed method encodes the data based on the number of WD-vulnerable cells and the bit flips. By reducing the number of WD-vulnerable cells as well as the bit flips, the proposed method is more effective than the existing encoding techniques, in mitigating WD as well as improving the memory lifetime. Evaluation using various realistic workloads shows that the proposed method can reduce the average word-line WD errors by 62%, compared to the existing state of the art. With a reduced number of WD errors, the frequency of a VnC operation is also reduced. This leads to a reduction of 44% in the number of extra writes and 20% in the average write time. With reduction in the number of writes and the write time, instructions-per-cycle is improved by 9% and the write energy by 11% over the existing art. By reducing the number of bit flips compared to the previous state of the art, the proposed method improves the PCM memory lifetime by 13% to 33%, considering the asymmetry of SET and RESET operations in impacting the cell endurance.
|Number of pages||14|
|Journal||IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems|
|Publication status||Published - 2022 Apr 1|
Bibliographical notePublisher Copyright:
© 1982-2012 IEEE.
All Science Journal Classification (ASJC) codes
- Computer Graphics and Computer-Aided Design
- Electrical and Electronic Engineering