Study of IC compatible on-chip thermoelectric coolers

A thin-film-based thermoelectric micro-cooler has been studied and realized using the standard integrated circuit (IC) fabrication technology and bulk micromachining technology in sequence. The whole fabrication process is kept IC compatible by postponing potassium hydroxide (KOH) etching step to the last part of the fabrication sequence. Considering the fabrication compatibility, polycrystalline silicon germanium (polySiGe) is chosen as thermoelectric material even though bismuth telluride (Bi₂Te₃) is one of the most effective thermoelectric materials. The influence of non-idealities on device performance, such as Joule heating due to contact resistance and parasitic heat loss through supporting membrane, is analyzed. The characterized thermoelectric, thermal and electric properties of the fabricated polySiGe thermoelectric material correspond well to those from literatures. Measured cooling performance demonstrates that an on-chip micro-cooler can be applied for thermal stabilization near ambient temperature.