Manufacturing thermoelectric micro-modules using micromachined silicon wafers

Recent technology requires the development of thermoelectric (TE) micro-modules used for the microgenerators and microcoolers. We are currently developing a novel process that could enable us to miniaturize TE modules to micrometer order. Our process includes three steps: 1) Periodically spaced deep micro-holes were generated on two surfaces of one piece of silicon wafer by the photolithography and reactive ion etching (RIE) techniques. 2) P- and N-type TE materials were separately cast or squeezed into the holes on each surface of the micromachined silicon mold. 3) After electrodes were formed by micromachining techniques, the silicon molds were removed by dry etching. The silicon molds with the holes of 300 gm deep and 40 gm square were successfully fabricated. Such a mold was covered with Bi-Sb-Te alloy powders and vacuum-encapsulated into a glass tube, which was then heated to a temperature above the melting point of the Bi-Sb-Te alloy in At gas of 1 MPa, as a result Bi-Sb-Te alloy rod arrays with a negative shape of the mold were obtained.