Nature of dark-brown SnO2 films prepared by a chemical vapor deposition method

Abstract

We recently found dark-brown SnO2 Alms were formed in a chemical vapor deposition process under a limited oxygen supplying condition and the nature was investigated in this work. Those films were deposited from SnCl 2 at 350-600°C in a tubular furnace. The Alms had the rutile-type structure with the significant preferred-orientation along <1 0 0> normal to the substrate surface. Thermogravimetric and elemental analyses revealed that the oxygen deficiency (Vo) and Cl contamination occurred in the films. An as-deposited film at 350°C contained Vo of 1.5 × 10 21 cm-3, which corresponded to that about 2.5% was vacant in the O site. On the other hand, Cl was contained at 7.4 × 10 20 cm-3 in the 350°C-prepared film. The Cl concentration decreased with deposition temperature and became 1.8 × 1020 cm-3 at 600°C. The Alms showed moderate electric-conductivity and the film deposited at 500°C had the lowest resistivity of 2.5 × 10-2 Ωcm, where the carrier density and the Hall mobility were 1.3 × 1020 cm-3 and 2.0 cm2 V-1s-1 respectively. © 2008 The Ceramic Society of Japan. All rights reserved.