A Review of MTJ Compact Models
11
A Review of MTJ Compact Models Richard Dorrance Advisor: Prof. Dejan Marković April 15, 2011 Literature Review
description
Literature Review. A Review of MTJ Compact Models. Richard Dorrance Advisor: Prof. Dejan Marković April 15, 2011. STT-MRAM and How it Works. STT = Spin-Torque-Transfer Use current to flip free layer between two resistive states. Compact Model Requirments. Bias Voltage. Temperature. - PowerPoint PPT Presentation
Transcript of A Review of MTJ Compact Models
Click to edit Master title style
A Review ofMTJ Compact Models
Richard DorranceAdvisor: Prof. Dejan Marković
April 15, 2011
Literature Review
STT-MRAM and How it Works
STT = Spin-Torque-Transfer– Use current to flip free layer
between two resistive states
2
Compact Model Requirments
3
50 100 150 200 250 300 350 400140
145
150
155
160
165
170
175
180
185
190
TM
R [
%]
Temperature [K]
Measured
Model
[1] J. D. Harms, et al. (U. Minnesota)
Switching time vs. current fitting. User defined delay for switching. SPICE.
4
[2] A. Nigam, et al. (UVA & Grandis)
Calculate the total transmission probability and density of available states (implemented in SPICE).
Accuracy: ±10% RP, RAP, TMR Physics based… I think…
5
Measured Model
[3] L.-B. Faber, et al. (U. Paris XI)
Model switching probabilities across several parameters. Switching based on user defined threshold and delay. Inaccurate below 10ns pulse widths.
6
Spectre Model
Switching Probabilities
[4] A. Raychowdhury, (Intel)
Uses a linearized LLGE, modified/fitted for thermally activated switching. Crude bias voltage approximation.
Semi- physics, semi-empirical.
7
[5] D. Datta, et al. (Purdue & UCB)
Uses a Non-Equilibrium Green’s Function (NEGF) based quantum transport model. (Physics Based)
8
Voltage Bias
Out of Plain Fields
[6] M. Madec, et al. (ULP)
Traditional LLGE model for precessional switching. Modified Jullière conductance model to include bias
voltage dependencies. Thermally activated switching not considered. VHDL-AMS implementation.
9
Limitations of Current Models
Few model bias voltage dependencies.
No published model incorporates temperature effects.
Empirical models cannot predict behavior.
Most physics models are too cumbersome for compact modeling.
Most models are ill-suited for incorporating statistical variation.
10
References
1. J. D. Harms, et al., “SPICE Macromodel of Spin-Torque-Transfer-Operated Magnetic Tunnel Junctions,” IEEE Transactions on Electron Devices, vol. 57, no. 6, pp. 1425-1430, June 2010.
2. A. Nigam, et al., “Self Consistent Parameterized Physical MTJ Compact Model for STT-RAM,” CAS 2010, vol. 2, pp. 423-426, Oct. 2010.
3. L.-B. Faber, et al., “Dynamic Compact Model of Spin-Transfer Torque Based Magnetic Tunnel Junction (MTJ),” DTIS '09, pp. 130-135, April 2009.
4. A. Raychowdhury, “Model Study of 1T-1STT MTJ” MWSCAS 2010, pp. 5-8, Aug. 2010.
5. D. Datta, et al., “Quantitative Model for TMR and Spin-Transfer Torque in MTJ Devices,” IEDM 2010, pp. 22.8.1-22.8.4, Dec. 2010.
6. M. Madec, et al., “Compact Modeling of Magnetic Tunnel Junction,” NEWCAS-TAISA 2008, pp.229-232, June 2008.
11
