Comparison of SnBr4 and di-n-butyl tin diacetate as laser-assisted chemical vapor deposition precursors for SnO2-based gas sensors

Abstract

Laser‐assisted chemical vapor deposition (LCVD) was utilized to produce SnO2 films from SnBr4 plus air, O2 or N2O. SnO2 films were successfully generated using either 222 or 308 nm laser pulses but there was evidence for film contamination when using less than 60 mJ/pulse laser energies at 222 nm. Films were characterized using ultraviolet absorption spectroscopy; the spectra of films with impurities resembled the spectrum of SnBr4. AFM images were obtained which indicated that this LCVD route produced small and fairly uniform SnO2 grains which were 50–100 nm in size. Multiphoton ionization spectroscopy was used to verify that the dissociation of a film dopant precursor, copper(II) acetate, produced gas‐phase copper atoms under conditions similar to those used in film deposition experiments. The deposition of SnO2 from SnBr4 plus an oxidant was found to be more efficient than from di‐n‐butyl tin diacetate but films produced via this new LCVD route, including those doped with copper, were found to be much less sensitive in preliminary gas‐sensing screening. © 1998 John Wiley & Sons, Ltd.

Elastic scattering of low-energy electrons by carbon, silicon, germanium and tin tetrahalides

“…Some of the molecules studied in this work are widely used as gas precursors in different processes involving low-temperature plasma. For example, SnCl 4 and SnBr 4 have been used for deposition of tin oxide (SnO 2 ) films [26][27][28][29][30], while CBr 4 has been used as an etching gas [31,32].…”