Study of thermoelectric properties of Bi/Te composite thin films by sputter deposition

• Main Author: 郭世偉
• Other Authors: 廖建能
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/986uqc

碩士 === 國立清華大學 === 材料科學工程學系 === 92 === With the evolution of VLSI process technology, component density of Integrated circuit(IC) increased significantly and heat dissipation is becoming a very important issue for device performance and IC reliability consideration. Due to the advantages of miniaturization and reliability, the thermoelectric refrigeration is attracting increasing attention recently. The performance of the thermoelectric refrigeration depends closely on the figure of merit(ZT) of the material. The Bi2Te3 compound semi- conductors are best known bulk thermoelectric materials near room temperature regime. In this study, thin film forms of the Bi2Te3 compound semiconductors were prepared by sputter deposition method. The Bi/Te bilayer thin films were deposited on SiO2 substrate in sequence, then transformed into Bi-Te compound by thermal treatment through solid state reation. The thickness ratio of Bi/Te bilayer structures and thermal annealing condition on the composite and the thermoelectric properties of the Bi-Te composite thin films was investigated. The results show that the Seebeck coefficient changed from -38.3μV/K to -201.3μV/K, the resistivity increased slightly from 2.02�e10-3μΩ-cm to 2.33�e10-3μΩ-cm, and the thermal conductivity decreased from 2.56 W/ m�枝 to 0.71 W/m�枝 when the Bi-Te composite thin films was annealed at 200℃ for 24 hours. The maximum ZT were 0.735 in this condition near room temperature. The compound phase was identified by x-ray diffraction technique, the morphology and the interdiffusion at the interface of Bi/Te bilayer thin films were examined by Scanning Electron Microscope(SEM).