Growth of SnO 2 thin films by atomic layer deposition and chemical vapour deposition: A comparative study

Abstract

Thin films of the tetragonal rutile-type SnO 2 phase have been deposited by both atomic layer deposition (ALD) and chemical vapour deposition (CVD) using the SnI 4–O 2 precursor combination. Depositions were carried out in the temperature region of 350–750 °C on α-Al 2O 3(0 1 2) substrates. In both cases the films were found to grow epitaxially with the in-plane orientation relationships [0 1 0] SnO 2 || [1 0 0] α-Al 2O 3 and [1 0 1¯] SnO 2 || [1¯ 2¯ 1] α-Al 2O 3 . 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.