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Thermal Management

Compact chip-scale cooling devices are of tremendous interest for high-heat flux thermal management in ever-shrinking electronic and optoelectronic systems. Increasing the thermal envelope will lead to higher computing performance from integrated circuit (IC) systems.

The RTI-Nextreme Electronics Hot Spot Cooler represents the first real-world demonstration of the application of nanoscale thermoelectric materials, whose scientific development in 2001 has led to significant research in the last decade. The results of RTI and Nextreme, with validation of the hot spot cooler by Intel, show great potential to significantly improve high-performance electronics technology.

RTI's early scientific results of this thermoelectric technology were published in Nature. Thin-film nanoscale superlattice materials, based on the concept of phonon-blocking electron transmission, have demonstrated

• Higher figure-of-merit (ZT~2.4 at 300K) at the individual thermoelement level
• Very high cooling power density for local cooling applications
• Very rapid cooling or heating
• Coefficient of performance similar to or better than current bulk thermoelectric technology, using 1/10,000th of the active material in conventional thermoelectrics

Using superlattice materials, we have demonstrated the first ever site-specific, on-demand cooling of heat fluxes over 1200 W/cm² on the active circuit side of the chip through solid-state cooling integrated into the chip package. See our paper "On-chip cooling by superlattice-based thin-film thermoelectrics" published in Nature Nanotechnology.

Citations and Patents

• Chowdhury I, Prasher R, Lofgreen K, Chrysler G, Narasimhan S, Mahajan R, Koester D, Alley R, Venkatasubramanian R (2009). On-chip cooling by superlattice-based thin-film thermoelectrics. Nature Nanotechnology 4 (4):235-238. Abstract | External Link | DOI:
• Bulman G, Siivola E, Wiitala R, Venkatasubramanian R, Acree M, Ritz R (2009). Three-stage thin-film superlattice thermoelectric multistage microcoolers with a ΔT max of 102 K. Journal of Electronic Materials 38(7):1510.
• Garimella SV, Fleischer AS, Murthy JY, Keshavarzi A, Prasher R, Patel C, Bhavnani SH, Venkatasubramanian R, Mahajan R, Joshi Y, Sammakia B, Myers BA, Chorosinski L, Baelmans M, Sathyamurthy P, Raad PE (2008). Thermal challenges in next-generation electronic systems. IEEE Transactions on Components and Packaging Technologies 31:801-815.
• Venkatasubramanian R, O'Quinn B, Alley R, Siivola E, Reddy A, Soto M, et al. (2005). Superlattice thermoelectrics for thermal management of electronics and optoelectronics. Proceedings of the InterPack 2005, ASME InterPack Conference, San Francisco, CA.
• Venkatasubramanian R, Siivola E, Colpitts T, O'Quinn B (2001). Thin-film thermoelectric devices with high room-temperature figures of merit. Nature 413 (6856):597-602. Abstract | External Link | News Release | RTI Author Award | DOI:
• Venkatasubramanian R (2009). Thin-film thermoelectric devices for hot-spot thermal management in microprocessors and other electronics. U.S. Patent No. 7,523,617. Washington, D.C.: U.S. Patent and Trademark Office.
• Venkatasubramanian R (2007). Thermoelectric devices utilizing double-sided Peltier junctions and methods of making the devices. U.S. Patent No. 7,235,735. Washington, D.C.: U.S. Patent and Trademark Office.
• Venkatasubramanian R (2007). Thin-film thermoelectric cooling and heating devices for DNA genomic and proteomic chips, thermo-optical switching circuits, and IR tags. U.S. Patent No. 7,164,077. Washington, D.C.: U.S. Patent and Trademark Office.