Miniature thermoelectric energy harvester and fabrication method thereof

摘要

A miniature thermoelectric energy harvester and a fabrication method thereof. Annular grooves are fabricated on a low-resistivity silicon substrate to define silicon thermoelectric columns, an insulating layer is fabricated on the annular grooves, a thermoelectric material is filled in the annular grooves to form annular thermoelectric columns, and then metal wirings, passivation layers and supporting substrates are fabricated, thereby completing the fabrication process. The silicon thermoelectric column using a silicon base material simplifies the fabrication process. The fabrication of the thermocouple structure is one thin-film deposition process, which simplifies the process. The use of silicon as a component of the thermocouple has a high Seebeck coefficient. The use of vertical thermocouples improves the stability. Since the thermocouple structure is bonded to the upper supporting substrate and lower supporting substrate by wafer-level bonding, the fabrication efficiency is improved.

主权项

1. A method for fabricating a miniature thermoelectric energy harvester, at least comprising:
1) providing a silicon substrate, and etching an upper surface of the silicon substrate to form at least two annular grooves, two neighboring of which are arranged at an interval, so that all the annular grooves and silicon columns surrounded by the annular grooves form a thermopile region; 2) forming an insulating layer on a surface of the annular groove, and then filling a thermoelectric material in the annular groove to form an annular thermoelectric column, so that the annular thermoelectric column and the silicon column surrounded by the annular thermoelectric column form a thermocouple; 3) fabricating an upper metal wiring to connect the silicon column and the annular thermoelectric column in a same thermocouple, and then fabricating an upper passivation layer on the upper surface of the silicon substrate; 4) providing an upper supporting substrate, and bonding the upper supporting substrate to the upper surface of the silicon substrate; 5) thinning the silicon substrate until a lower surface of the thermocouple is exposed; 6) fabricating a lower metal wiring to connect the annular thermoelectric column and the silicon column in two neighboring annular thermocouples, and then fabricating a lower passivation layer on a lower surface of the silicon substrate; 7) etching the silicon substrate between two neighboring thermocouples to form an isolation structure; and 8) providing a lower supporting substrate, and bonding the lower supporting substrate to the lower surface of the silicon substrate, thereby completing fabrication of a miniature thermoelectric energy harvester.