The effect of bias voltage on the morphology and wettability of plasma deposited titanium oxide films

Hydrophobic and hydrophilic films with titanium oxide inside were grown by radio frequency plasma enhanced chemical vapor deposition (RF--PECVD) on glass substrates. Bias voltage was used as an assistant for the deposition process. And a comparison was made between with and without the bias voltage. Titanium tetraisopropoxide (TTIP-Ti (OC3H7)(4)) was used as the precursor compound. Film wettability was tested by water contact angle measurement (CAM). The water contact angle (WAC) of the film deposited in plasma without biased voltage was greater than 1450, while the WAC of the film deposited in plasma with biased voltage was less than 30 degrees. The morphology of the deposited films was observed by scanning electron microscope (SEM). It is found that the films grown without bias voltage were covered with lots of nano grain and pores, but the surface of the films deposition with bias voltage was much dense. The chemical structure and property of the deposited films were analyzed by Fourier-transformed infrared spectroscopy (FTIR), while the plasma phase was investigated by optical emission spectroscopy (OES).