DIELECTRIC-PROPERTIES OF FLUORINATED SILICON DIOXIDE FILMS

Amorphous fluorinated Si dioxide (a-SiO2:F) films were deposited at 30 0 degrees C by plasma-enhanced chemical vapor deposition (PECVD) using SiH4-O-2-CF4 mixtures with different RF power and deposition temperat ures T-d. Their bonding and dielectric properties were investigated. T he F content, deposition rate and dielectric constant, epsilon(s), dec reased and water resistance improved as either RF power or T-d increas ed. However, for obtaining a him with both small epsilon(s) and high w ater resistance, the value of epsilon(s) was limited to epsilon(s) app roximate to 3. It is proposed that increased water absorption could be caused by occurrence of high tensile stress in the films, and that hi gh-decomposition rates of CF4, high-energy ion bombardment and/or easi er surface migration of adsorbates during film growth, caused by incre asing RF power or T-d, act to remove weak Si-O and Si-F bonds, resulti ng in films with low epsilon(s) and high water resistivity. (C) 1998 E lsevier Science B.V. All rights reserved.