Thin films of titanium dioxide (TiO2) with desired crystal phase of anatase or rutile were formed by rf sputtering of a TiO2 target under precisely controlled process parameters. The application of TiO2 as the antireflection layers of a TiN-based heat mirror was testified. Optical calculation was done for the heat mirror, and an optimized structure with TiO2 (30 nm)/TiN (30 nm)/TiO2 (30 nm) was deposited on SiO2 glass by sequential sputtering. Optical evaluation of the heat mirror was performed by measuring the transmittance/reflectance with a spectrophotometer in wavelengths 250-2500 nm and with a FT-IR system in wavelengths 1-25 mum, respectively. Furthermore, it is suggested that a better and a multifunctional performance can mostly be expected through precise control of the crystal structure of the TiO2 top layer which acts as a photocatalyst. (C) 2003 Published by Elsevier Science B.V.