Low emissivity high-temperature tantalum thin film coatings for silicon devices

Journal Article · Tue Jan 01 00:00:00 EST 2013 · Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films

DOI:https://doi.org/10.1116/1.4766295· OSTI ID:1081196

Rinnerbauer, Veronika ^[1]; Senkevich, Jay J. ^[1]; Joannopoulos, John D. ^[1]; Soljacic, Marin ^[1]; Celanovic, Ivan ^[1]; Harl, Robert R. ^[2]; Rogers, Bridget R. ^[2]

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1. MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States). Inst. of Soldier Nanotechnologies
2. Vanderbilt Univ., Nashville, TN (United States)

The authors study the use of thin ( ~230 nm ) tantalum (Ta) layers on silicon (Si) as a low emissivity (high reflectivity) coating for high-temperature Si devices. Such coatings are critical to reduce parasitic radiation loss, which is one of the dominant loss mechanisms at high temperatures (above 700 °C ). The key factors to achieve such a coating are low emissivity in the near infrared and superior thermal stability at high operating temperatures. The authors investigated the emissivity of Ta coatings deposited on Si with respect to deposition parameters, and annealing conditions, and temperature. The authors found that after annealing at temperatures ≥900 °C the emissivity in the near infrared ( 1–3 μm ) was reduced by a factor of 2 as compared to bare Si. In addition, the authors measured thermal emission at temperatures from 700 to 1000 °C , which is stable up to a heater temperature equal to the annealing temperature. Furthermore, Auger electron spectroscopy profiles of the coatings before and after annealing were taken to evaluate thermal stability. A thin (about 70 nm) Ta₂O₅ layer was found to act as an efficient diffusion barrier between the Si substrate and the Ta layer to prevent Si diffusion.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC)
• Sponsoring Organization: USDOE
• DOE Contract Number: SC0001299; FG02-09ER46577
• OSTI ID: 1081196
• Journal Information: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Vol. 31, Issue 1; Related Information: S3TEC partners with Massachusetts Institute of Technology (lead); Boston College; Oak Ridge National Laboratory; Rensselaer Polytechnic Institute; ISSN 0734-2101
• Publisher: American Vacuum Society
• Country of Publication: United States
• Language: English

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