<title>Modifications of DLC films for MEMS applications</title>

Abstract

SiO-containing DLC films are deposited by plasma enhanced chemical vapor deposition on Si substrate. The effect of SiO, dopants on the stress, adhesion and hydrophobicity of the DLC films are studied. The incorporation of SiO, in the DLC films deposited by using hexamethyldisiloxane(HMDSO) and CH4 mixture reduces the residual stress as well as enhances adhesion ofthe film on the substrate. Besides, the thermal stability ofthe film also improves.The incorporation of SiO, in the DLC film, as deposited by using HMDSO/CH4 mixture, can raise the water contact angle from 95°, as for the pure DLC film, to 1 10°. IR results show that the increase of contact angle is mainly due to the incorporation of a higher concentration of -CH3 group in the HMDSO-deposited films. By adding 02 with HMDSO, the contact angle of the deposited film can be reduced to 27°, showing hydrophilic property. By enhancing the surface roughness, the water contact angle can be further increased to 145° for the hydrophobic films deposited using HMDSO/CH4, and the water contact angle can be further reduced to 3° for the hydrophilic films deposited using HMDSO/02.