CEA. All rights reserved. L. Perniola – Workshop on Innovative Memory
Technologies | June, 29, 2011 | 2. « Robustness » for embedded applications.
Investigation of new chalcogenide materials to improve the PCM robustness L. Perniola
« Robustness » for embedded applications • • • • •
High scalability High endurance Low power consumption High programming speed 10 years data retention at 85°C with GST Intel-STM
B.Gleixner et al. IRPS 2007
Improvement may come from material engineering
SAMSUNG
J.H.Oh et al. IEDM 2006
L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 2 © CEA. All rights reserved
Power consumption & endurance
State of the art: doping species GST provides some clues on suitable doping species Carbon doping
Nitrogen doping
Ovonix, EPCOS 2006
S. Ahn & Y.N. Hwang, SAMSUNG, IEDM 2004
H. Horii, SAMSUNG, VLSI 2003
L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 3 © CEA. All rights reserved
State of the art: GeTe host material
Data Retention
Alternative to GST suitable host material: In-Ge-Te
Ge4Sb1Te5+ SiOx
T. Morikawa, Hitachi, IEDM 2007
L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 4
W. Czubatyj, Ovonyx,©EDL 2010 CEA. All rights reserved
State of the art: GeTe host material
Optical domain
Philips: (Coombs & al., APL 1995) Ge0.4Te0.6 & Ge0.6Te0.4 are slower strongly growth-controlled PC (ie ~200500 ns) Behavior not due to material segregation but due to different chemical properties
IBM-Macronix (S. Raoux, APL 2009) Crystallization process GexTey all growth-controlled
L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 5 © CEA. All rights reserved
Aim of the work: doped GeTe PCM Strong variation of RESET current in GST-C and GST-N Enhancement of data retention perfs in Ge4Sb1Te5+ SiOx and In-GeTe large speed variation fct of GexTey (optical domain)
Accurate analysis of C and N doping impact in GeTe
L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 6 © CEA. All rights reserved
GeTeC: Optical reflectivity & electrical resistivity
TC GeTe
~180°C
GeTeC4%
~300°C
GeTeC10%
~370°C
Strong enhangement of Tc Slower transition for higher C-doping G. Betti Beneventi, IMW 2010 L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 7 © CEA. All rights reserved
GeTeC: RESET current reduction 30 nm-thick GeTeC integrated in PCM
GeTeC4%: IRESET -10% wrt GST GeTeC10%: IRESET -30% wrt GST G. Betti Beneventi, IMW 2010 L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 8 © CEA. All rights reserved
GeTeC: R-V programming characteristics* GeTe
• Raising C content
GeTeC4%
GeTeC10%
Slow down of SET speed Reduction of VRESET
* Each test is an average on ~10 cells
G. Betti Beneventi, ESSDERC 2010
L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 9 © CEA. All rights reserved
GeTeC: Data retention @ fixed T & extrapolation*
Fail temperature @ 10 y GeTeC10%
~127°C
* Each characteristics is the median of a population of > 30 cells G. Betti Beneventi, ESSDERC 2010 L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 10 © CEA. All rights reserved
A. Fantini, IEDM 2010 L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 11 © CEA. All rights reserved
No IRESET reduction
100 nm-thick GeTeN
A. Fantini, IEDM 2010 L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 12 © CEA. All rights reserved
A. Fantini, IEDM 2010 L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 13 © CEA. All rights reserved
GexTey: Data Retention 5
10
5
10
Fail time [s]
Resistance [Ω]
6
10
4
10
3
10
2
10 10
1
165°C 170°C 180°C 190°C 200°C 10
54 devices under test
Ge30Te70 2
3
10 10 Time [s]
4
10
5
10
EA
TFAIL(10y)
Ge50Te50
2.2 eV
95 °C
Ge40Te60
3.1 eV
117 °C
Ge30Te70
3.6 eV
126 °C
4
10
Ge30Te70 Ge40Te60 Ge50Te50
3
10
2
10
10
24.5 25
25.5 26 26.5 27 1/(KBT) [eV-1]
Raising Te at. %: Enhanced stability of RESET-state G. Navarro, IMW 2011 N. Pashkov, to be presented @ ESSDERC 2011
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Conclusion GeTe host material features robustness for embedded applications in terms of: RESET current reduction: GeTeC10% up to ~30% Ge30Te70 up to ~25% RESET current reduction comes at a tradeoff on programming time (SET operation) ~1 decade longer Data retention: 100 nm-thick GeTeN2% TFAIL @ 10 yrs~154°C 100 nm-thick Ge30Te70 TFAIL @ 10 yrs~126°C 30 nm-thick GeTeC10% TFAIL @ 10 yrs~127°C
L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 15 © CEA. All rights reserved
Acknowledgement V. Sousa, G. Navarro, N. Pashkov, M. Suri, E. Henaff, A. Persico, F. Fillot, F. Pierre, A. Roule, S. Maitrejean, H. Feldis, C. Jahan, J. F. Nodin, A. Toffoli, D. Blachier, A. Bastard, J-C. Bastien, B. Hyot, B. André, G. Reimbold, B. De Salvo, O. Faynot E. Palumbo, P. Zuliani and R. Annunziata of ST-Agrate ePCM LETI-ST project
L. Perniola – Workshop on Innovative Memory Technologies | June, 29, 2011 | 16 © CEA. All rights reserved
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