ICT2014 Abstracts

Recently thermoelectric thin film devices, which can produce micro power generation by energy harvesting with minor temperature differences produced by body heat, have been extensively investigated as potential power sources for wearable electronics. Thermoelectric thin film devices have advantages of high power density, long lifetime, and high reliability with no moving parts. Thermoelectric thin film devices can be classified as either in-plane or cross-plane devices based on the direction of a heat flow against a substrate. An in-plane or planar device, where heat flows parallel to a substrate, is relatively easier to process. However, its internal resistance is usually high, making it unsuitable for power generation applications. On the other hand, a cross-plane device, where a heat-flow direction is perpendicular to a substrate, has low electrical resistance and is suitable for micro power generation. For a cross-plane thin film device, bonding of upper electrodes in a top substrate to thermoelectric thin film legs in a bottom substrate is one of the most difficult process steps and the power generation characteristics would be drastically changed by the integrity of the flip chip joints. In this study, we processed cross-plane thin film devices consisting of n-type Bi2Te3 and p-type Sb2Te3 thin film legs using electrodeposition and flip chip bonding, and characterized their power generation characteristics. Maximum output powers of 1 mW and 4.4 mW were obtained at temperature differences of 20K and 43K, respectively, across the thin film devices.

Acknowledgement

This work was supported by the Basic Science Research Program of the National Research Foundation of Korea (Project No.: 2011-0029443).