Self-standing Polysilicon-metal Thermopile for Micro Power Generator

Abstract

A prototype self-standing polysilicon-metal junction thermopile has been developed. In order to realize ideal higher thermal isolation, a thermopile without a membrane and having self-standing structure is proposed. It is arbitrary to select the heat absorber or the substrate as a hot contact, i.e. the hot and cold contacts can be inverted. The thermocouple is composed of an n-type polysilicon and an Au junction. The thermopile was fabricated by MICS (Multi-user Integrated Chip Service: three polysilicon layer structure) organized by the Cooperative Research Committee for Standardization of Micromachines in IEE of Japan. Output characteristics were measured as a function of distance between the hot contact of the thermopile and the radiation source, in order to confirm performance of the proposed thermopile as an accessory micro power generator. Seebeck voltage of more than 6.2mV was obtained in the case of connecting ten thermocouples is series for typical human skin (307K) used as a radiation source.