Investigation of reactive magnetron sputtering of indium tin oxide films on acrylics - Lattice parameters and stoichiometric compositions

Indium tin oxide films were deposited on acrylics by reactive magnetron spu ttering at a low substrate temperature for their application to pilot windo ws. The effects of oxygen flow on the microstructure and chemical compositi on of films were explored. The deposition rate of ITO films invariably incr eased with the cathode current and decreased with the bias voltage. In addi tion, it initially decreased significantly with increasing oxygen flow rate but this decrease slowed down as the oxygen flow rate exceeded a certain c ritical value. The composition of ITO films is considerably different from the stoichiometric composition. However the O/(In + Sn) ratio approached th e stoichiometric composition with the increase in the oxygen flow rate. No obvious crystalline phases were detected in ITO films at an oxygen flow rat e of 1 sccm. However crystalline phases were observed as the oxygen flow ra te increased. The lattice parameters of ITO films increased with the oxygen flow rate and were greater than that of In2O3. This was attributed to the decrease in oxygen vacancies at high flow rates. Low-energy (110) planes gr ow preferentially in ITO films with no bias voltage. Non-close-packed prefe rential planes of (111) predominated, however, as the bias voltage was incr eased.