A systematic investigation and statistical analysis of thermal Atomic Layer Deposition (ALD) process parameters on TiO2 thin film deposition rate using designed experiments

Deposition rate is a challenge in Atomic Layer Deposition (ALD) due to its atomic fashion of depositing materials on substrate surface. TiO₂ thin film is one of the most deposited materials by ALD due to its desirable properties. Design of Experiments (DOE) is a powerful method for studying ALD processes, but it has not been extensively adopted by ALD researchers. This study employed a 2⁴ full factorial DOE to analyze the effects of deposition temperature, inert gas flow rate, pulsing time, and purging time on TiO₂ thin film growth rate by thermal ALD using TDMAT and water. Statistical analysis identified deposition temperature and purging time as the most significant factors while pulsing time was mildly significant, and the gas flow rate was nonsignificant. A mild interaction was found between temperature and purging time. Optimal condition was identified at 150 °C temperature, 10 s purging, and 600/60 ms pulsing to increase the deposition rate.