| AVS 55th International Symposium & Exhibition | |
| Thin Film | Thursday Sessions |
| Session TF-ThA |
| Session: | Thin Films for Displays and Flexible Electronics |
| Presenter: | H. Chandra, General Plasma Incorporated |
| Authors: | H. Chandra, General Plasma Incorporated M.A. George, General Plasma Incorporated S. Higgins, General Plasma Incorporated P.L. Morse, General Plasma Incorporated J.E. Madocks, General Plasma Incorporated |
| Correspondent: | Click to Email |
Transparent conducting oxide (TCO) is a key component for photovoltaic and display applications. Indium tin oxide (ITO) is the best known TCO material with regard to electrical and optical properties. However, ITO is prohibitively expensive for economical production for these applications. One candidate to replace ITO as TCO material is fluorine-doped tin oxide. It is stable at high temperature, economical to produce and less reactive compared to other TCO materials such as zinc-oxide based TCO1. The bulk resistivity of tin oxide films deposited with conventional method (PECVD, spray pyrolysis, atmospheric pressure CVD) is as low as 2x10-4 Ohm-cm.1 However, the deposition temperature is typically above 350°C which has limited use for temperature sensitive processes such as quantum dots based solar cells or large area plastic substrates. We have developed a novel PECVD system to deposit tin oxide at lower temperature (below 200°C) while achieving good conductivity. Our tin oxide films have bulk resistivity below 4x10-3 Ohm-cm at 200°C which is lower than conventionally deposited films at the same process temperature. Furthermore, the linear PECVD source used in this process is scalable to several meter-wide web substrates with film uniformity better than 3%. The deposition rate is typically 200-400 nm-meter/minutes more than an order of magnitude higher than competing sputtering technologies. The scalability to large area with excellent uniformity coupled with high deposition rate is important for economical production of TCO layer. In the present work, we will discuss the PECVD source used in the process, electrical properties (carrier concentration and mobility), optical properties and microstructure of the deposited tin oxide and other TCO thin film materials.
1W. Beyer et al., “Transparent conducting oxide films for thin films silicon photovoltaics,” Thin Solid Films 516, 147 (2007).