Author :
Khwa, W.S. ; Wu, J.Y. ; Su, T.H. ; Lee, M.H. ; Li, H.P. ; Chen, Y.Y. ; BrightSky, M. ; Wang, T.Y. ; Hsu, T.H. ; Du, P.Y. ; Chien, W.C. ; Kim, S. ; Cheng, H.Y. ; Lai, E.K. ; Zhu, Y. ; Chang, M.F. ; Lung, H.L. ; Lam, C.
Author_Institution :
Macronix Int. Co., Ltd., Hsinchu, Taiwan
Abstract :
Inherent cell variation of phase change memory is difficult to control by material or device engineering alone. We previously reported R-I curve shift detection scheme as a good method for monitoring PCM cell characteristics. This paper extends that concept and proposes a Stress-trim procedure to tighten R-I characteristics for PCM MLC operation. By leveraging the right-shift phenomena of PCM R-I curves, we demonstrated that Stress-trim can effectively reduce cell variation to improve MLC performance. A MLC program current amplitude range reduction of 40% and MLC time to failure extension of nearly 150X are achieved.
Keywords :
phase change memories; MLC program current amplitude range reduction; MLC time to failure extension; cell variation; multi-level-cell performances; phase change memory; stress-trim procedure; Electrical resistance measurement; Monitoring; Phase change materials; Phase change memory; Resistance; Stress; Stress measurement;
