Wafer-level vacuum sealing and encapsulation for fabrication of CMOS MEMS thermoelectric power generators

This paper presents technologies of wafer-level vacuum sealing and encapsulation at low temperature with CMOS compatible process and materials for fabrication of thermoelectric power generators (TPGs). A novel design of TPG with thermal legs embedded in the cavities is proposed. Results of simulation validate that the two cavities maximize the temperature difference between the hot and cold junctions of thermocouples. With the verified technologies of wafer-level vacuum sealing and encapsulation, a thermoelectric power generator is developed based on heavily p- and n-doped polysilicon. The fabricated power generator has a power efficiency factor of 0.052 ¿Wcm^-2K^-2.