Atmospheric pressure deposition of SnO₂ and ZnO

Transparent conductive oxide (TCO) coated glass is widely used in thin film PV. Atmospheric pressure chemical vapor deposition (APCVD) is a highly cost effective method of deposition and apart from metal precursor and oxygen precursor, other additives can improve the layer quality. In this contribution, we present an overview of the latest results on SnO₂ and ZnO work. First, the beneficial effect of methanol addition is discussed. By adding methanol during the SnO₂ deposition, the conductivity increased up to ten times, with remarkably high mobility values of up to 55 cm²/Vs. The films are already very conductive at a thickness below 10 nm. This is highly beneficial to applications with strict requirements in terms of film transparency. For ZnO:Al the APCVD process was developed with a deposition rate of 14 nm/s for one injector and resistivity values down to 0.6 mΩ cm. Low temperature APCVD ZnO was achieved by introducing remote plasma in the system. Deposition rate of 7 nm/s and resistivities of 2 mΩ cm were obtained. For spatial ALD, growth rates of ZnO were up to 1 nm/s and resistivities were of the order of 4 mΩ cm.