Free-standing planar thin-film thermoelectric microrefrigerators and the effects of thermal and electrical contact resistances

• Published in: International journal of heat and mass transfer 2018-02, Vol.117, p.436-446
• Main Authors: Su, Yu, Lu, Jianbiao, Huang, Baoling
• Format: Article
• Language: English
• Subjects: Biocompatibility; Bismuth tellurides; Computer simulation; Contact resistance; Convection; Cooling; Electric contacts; Heat resistance; Heavy metals; Integrated circuits; Low temperature resistance; Mathematical models; Microelectronics; Planar structure; Refrigerators; Response time; SiGe thin film; Silicon germanides; Thermal management; Thermoelectric cooling; Thermoelectric microrefrigerator; Thermoelectricity; Thin films
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2017.10.023

•A free-standing thin-film planar thermoelectric microrefrigerator based on IC-compatible materials is proposed.•An analytical model describing the behaviors of the proposed microrefrigerator is developed and verified.•Design strategies for optimizing the performance with the consideration of contact resistance are explored.•Thermoelectric microrefrigerators prototypes based on SiGe thin films with a potential cooling temperature of more than 20K are developed. Thermoelectric microrefrigerators provide an attractive solid-state solution for on-chip thermal management of microelectronics due to their unique advantages. Here we propose a free-standing planar design of thermoelectric microrefrigerator based on thin film technologies to address the high-performance on-chip cooling and compatibility with microelectronics fabrication. By combining theoretical modeling, numerical simulations and experiments, we conducted a comprehensive investigation of the steady-state and transient performances of the proposed microrefrigerators and various factors that might influence their performance, such as contact resistances, element geometries, convection and radiation, have been explored. Both thermal and contact resistances are found to be important for the cooling performance of the proposed microrefrigerators while they play different roles on the cold and hot sides of a refrigerator. The influence of contact resistances on the design strategies of a microrefrigerator is also discussed. It is demonstrated that microrefrigerators based on IC-compatible low-cost SiGe thin films can potentially achieve a cooling temperature more than 20K with a response time shorter than 40ms near room temperature, rendering them competitive against the state-of-the-art microrefrigerators based on toxic conventional heavy metal thermoelectrics such as Bi2Te3 and Sb2Te3.