Exploring the Potential of Phase Change Memories as an Alternative to DRAM Technology

Scalability poses a severe threat to the existing DRAM technology. The capacitors that are used for storing and sensing charge in DRAM are generally not scaled beyond 42nm. This is because; the capacitors must be sufficiently large for reliable sensing and charge storage mechanism. This leaves DRAM memory scaling in jeopardy, as charge sensing and storage mechanisms become extremely difficult. In this paper we provide an overview of the potential and the possibilities of using Phase Change Memory (PCM) as an alternative for the existing DRAM technology. The main challenges that we encounter in using PCM are, the limited endurance, high access latencies, and higher dynamic energy consumption than that of the conventional DRAM. We then provide an overview of various methods, which can be employed to overcome these drawbacks. Hybrid memories involving both PCM and DRAM can be used, to achieve good tradeoffs in access latency and storage density. We conclude by presenting, the results of these methods that makes PCM a potential replacement for the current DRAM technology.

Authors:

• Venkataraman Krishnaswami
• Venkatasubramanian Viswanathan

Keywords:

• DRAM
• Phase Change Memory.

References:

[1] S. Thoziyoor, J. H. Ahn, M. Monchiero, J. Brockman, N. P. Jouppi, "A
Comprehensive Memory Modeling Tool and its Application to the
Design and Analysis of Future Memory Hierarchies," The 35th
International Symposium on Computer Architecture, pp.51-62, 2008.
[2] Benjamin C.Lee, Egin Ipek et.al. "Architecting Phase Change Memory
as Scalable DRAM Alternative". ISCA-09, Austin, Texas, USA.
[3] Moinuddin K. Qureshi, Vijayalakshmi Srinivasan Jude A. Rivers
"Scalable High Performance Memory Systems Using Phase Change
Memory Technology" Proceedings of the 36th annual international
symposium on Computer architecture 2009.
[4] Ping Zhou et.al, "A durable and energy efficient Main Memory using
Phase Change Memory Technology" ISCA 2009
[5] A. Pirovano, A. Lacaita, A. Benvenuti, F. Pellizzer, S.Hudgens, R. Bez,
"Scaling Analysis of Phase-Change Memory Technology," IEEE
International Electron Devices Meeting, pp. 29.6.1-29.6.4, 2003.
[6] Y. Chen et al. "Ultra-thin phase-change bridge memory device using
GeSb." In International Electron Devices Meeting, 2006
[7] H. Horii et al. "A novel cell technology using N-doped GeSbTe films
for phase change RAM". In Symposium on VLSI Technology, 2003.
[8] Andre Seznec, "A Phase Change Memory as a Secure Main Memory,"
IEEE Computer Architecture Letters, vol. 9, no. 1, pp. 5-8, Jan.-June
2010, doi:10.1109/L-CA.2010.2
[9] Matthew J. Breitwisch "Phase Change Memory", IBM/Macronix
PCRAM joint project aibm t j Watson Research Centre Yorktown
heights, New York USA 2008.
[10] Matthias Wutting "Towards Universal Memories
Exploring the Potential of Phase Change Memories" International
Symposium on VLSI Technology, Systems and Applications, 2007.