Thin films of the tetragonal rutile-type SnO2 phase have been deposited by both atomic layer deposition (ALD) and chemical vapour deposition (CVD) using the SnI4-O2 precursor combination. Depositions were carried out in the temperature region of 350-750 degrees C on Phi-Al2O3 (0 1 2) substrates. In both cases the films were found to grow epitaxially with the in-plane orientation relationships [0 1 0]SnO2 vertical bar vertical bar [1 0 0]alpha-Al2O3 and [1 0 (1) over bar ]SnO2 vertical bar vertical bar [(1) over bar (2) over bar 1]alpha-Al2O3. Films grown by ALD were found to be close to perfectly single crystalline, contained a low density of defects and were almost atomically smooth. The CVD films were found to have a much rougher film morphology, and exhibited both grain boundaries and twin formation. (c) 2006 Elsevier B.V. All rights reserved.