Thermoelectric characteristics of Pt-silicide/silicon multi-layer structured p-type silicon

Abstract

Electric mid thermoelectric properties of suicide/silicon multi-layer structured devices were investigated with the variation of suicide/silicon heterojunction numbers from 3 to 12 layers. For the fabrication of silicide/silicon multi-layered structure, platinum and silicon layers are repeatedly sputtered on the (100) silicon bulk substrate and rapid thermal annealing is carried out for the silicidation. The manufactured devices show ohmic current-voltage (I-V) characteristics. The Seebeck coefficient of bulk Si is evaluated as 195.8 +/- 15.3 mu V/K at 300 K, whereas the 12 layered suicide/silicon multi-layer structured device is evaluated as 201.8 +/- 9.1 mu V/K. As the temperature increases to 400 K, the Seebeck coefficient increases to 237.2 +/- 4.7 mu V/K and 277.0 +/- 1.1 mu V/K for bulk and 12 layered devices, respectively. The increase of Seebeck coefficient in multi-layered structure is mainly attributed to the electron filtering effect due to the Schottky barrier at Pt-silicide/silicon interface. At 400 K, the thermal conductivity is reduced by about half of magnitude compared to bulk in multi-layered device which shows the efficient suppression of phonon propagation by using Pt-silicide/silicon hetero-junctions.