ABSTRACT
Bismuth, antimony, and tellurium compounds (Bi/Sb/Te) are known as the best thermoelectric materials for room-temperature operation. Despite thermoelectric devices with these materials being used for many years in macroscale dimensions (millimetres sized devices), only few attempts were made to reduce these devices to the microscale (micrometer-sized devices). še deposition of thermoelectric œlms was reported before using techniques like electrochemical deposition (ECD), metal-organic chemical vapor deposition (MOCVD), pulsed laser deposition, sputtering, and thermal evaporation [1-8]. Each technique has its advantages and disadvantages, and a summary can be found in Table 19.1. In the table, CVD and ECD present opposite characteristics: while CVD œlms present high œgure of merit (ZT), but a low deposition rate and expensive and complicated equipment is required (speciœc gases are needed for the deposition), ECD is a simple process, allowing high deposition rates (tens of micrometers can be achieved) but resultant œlms present low ZT. However, ECD allows the creation of structures during the deposition process, using the LIGA process (from German “lithographie, galvanoformung, abformung,” meaning lithography, electroplating, and molding). In this chapter, the deposition of Bi2Te3 and Sb2Te3 thin œlms by thermal coevaporation is described.
