HIGHLY ORIENTED DOPED AND UNDOPED TIN OXIDE THIN FILMS GROWN ON MULTICRYSTALLINE SILICON SUBSTRATE

Abstract

Polycrystalline antimony doped and undoped tin oxide thin films are grown by chemical vapor deposition on multicrystalline silicon and on glass substrates. The latter substrate was considered for comparative study on growth and characterization. The doping was achieved with various content of Sb in the starting material. X ray diffraction patterns let us to find preferential growth which is not the same according to the substrate. On the glass substrate the grain grows in the (101, 211, 200) crystallographic direction while it grows in the (110, 211, 101) orientation when deposited on
polycrystalline silicon substrate at the same time and in the same reactor. The resultant films possess a columnar microstructure perpendicular to the substrate and exhibits grains with nanometer size. The sheet resistance measured on doped layers are significantly improved compared to that obtained on undoped ones, in the same conditions i.e. substrate temperature Ts=440°C, duration of the deposition 10 min and flowing oxygen about 2L/min. Contrary to results obtained on tin oxide layer deposited on monocrystalline silicon in previous work the microstructure seems to be dependant on the kind of the substrate.