Materials Sciences and Applications, 2012, 3, 645-649 http://dx.doi.org/10.4236/msa.2012.39094 Published Online September 2012 (http://www.SciRP.org/journal/msa) 645 Preparation of Thin Films by a Bipolar Pulsed-DC Magnetron Sputtering System Using Ca 3 Co 4 O 9 and CaMnO 3 Targets Weerasak Somkhunthot 1 , Nuwat Pimpabute 1 , Tosawat Seetawan 2 1 Program of Physics and Science Center, Faculty of Science and Technology, Loei Rajabhat University, Loei, Thailand; 2 Thermoelectrics Research Center, Faculty of Science and Technology, Sakon Nakhon Rajabhat University, Sakon Nakhon, Thailand. Email: t_seetawan@snru.ac.th Received June 7 th , 2012; revised July 2 nd , 2012; accepted August 5 th , 2012 ABSTRACT The thin films were deposited on the glass substrates by an asymmetric bipolar pulsed-dc magnetron sputtering system using the Ca 3 Co 4 O 9 (p-type) and CaMnO 3 (n-type) targets of 60 mm diameter and 2.5 mm thickness. The targets were prepared from powder precursors, which obtained by a solid state reaction. Optical emissions from plasmas during sputter depositions of films were detected using a high resolution spectrometer. Thickness of thin film was estimated by Tolansky’s Fizeau fringe method and ellipsometic measurement. Crystal structures were studied from X-ray diffraction. The thermoelectric properties were assessed from Seebeck coefficient and electrical resistivity measurements at room temperature. The power factors were calculated. It was found that the optical emission spectrums showed that the Ca, Mn, Co and O atoms were sputtered from the targets onto glass substrates. As-deposited Ca-Co-O and Ca-Mn-O films thickness values were 0.435 m and 0.449 m, respectively. The X-ray diffraction patterns clearly showed amorphous nature of the as-deposited films. Determining thermoelectric properties of Ca-Co-O film gave Seebeck coefficient of 0.146 mV/K, electrical resistivity of 0.473 cm, and power factor of 4.531 µW/mK at room temperature. Ca-Mn-O film baring a high resistance was not the experimental determination of thermoelectric properties. Keywords: Thermoelectric Thin Film; Ca 3 Co 4 O 9 ; CaMnO 3 ; Bipolar Pulsed-DC Magnetron Sputtering System 1. Introduction In the past, the metal coating in form of thin films to im- prove the quality of material was done by electroplating process which is often also called electro-deposition. The disadvantage of electroplating was harmful to the environ- ment. Subsequently, the vacuum depositions were devel- oped in chemical vapor deposition (CVD) and physical va- por deposition (PVD). CVD is a technique whereby gase- ous reactants can be deposited onto a substrate. However, often dangerous by-products are removed by gas flow. PVD is a clean coating technology that involves evaporation and deposition of a material. Material vaporizes are removed from a source by physical processes such as evaporation sputtering and it is transported in the form of a vapor atomic beam through a vacuum to the substrate. Magnetron sput- tering is one of PVD methods, which are widely used in thin film technology. The various types of magnetron sput- tering technique are direct current (DC), alternating current (AC), radio frequency (RF), and pulsed-dc [1]. Pulsed-dc magnetron sputtering is one of the latest developments of sputtering technology for thin films deposition, which has many advantages over others. Namely, it is versatile and provides the ability to deposit thin films of oxide com- pounds at high deposition rate and to eliminate arcing problems of poisoned targets [2]. This is interested to apply the deposition technology. It may be possible to customize the deposition conditions so that the thin films of highly preferred orientation can be grown. In this work, the depositions of thin films have been car- ried out by a bipolar pulsed-dc magnetron sputtering sys- tem using the Ca 3 Co 4 O 9 and CaMnO 3 targets, which were made from powder precursors obtained from the solid state reaction (SSR) route. Optical emissions from plasmas dur- ing sputter deposition of thin films were measured using a high resolution spectrometer. Crystal structures of the as- deposited films were studied from X-ray diffraction (XRD). The thickness of thin films and thermoelectric properties were investigated. 2. Experimentation The preparation of thin films by a pulsed-dc magnetron sputtering system is shown in Figure 1 [3]. The details of Copyright © 2012 SciRes. MSA