Stabilizing dielectric constant of fluorine-doped SiO 2 film by N 2O and NH 3 plasma post-treatment

• Published in: Thin solid films Vol. 308; pp. 501 - 506
• Main Authors: Mei, Y.J, Chang, T.C, Chang, S.J, Pan, F.M, Chen, M.S.K, Tuan, A, Chou, S, Chang, C.Y
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1997
• Subjects: Fluorine dope oxide; Low dielectric; Plasma post-treatment; Low dielectric; Plasma post-treatment; Fluorine dope oxide
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(97)00482-3

Fluorine doped oxide (SiO 2-xF x) films have been found to exhibit a low dielectric constant. However, the critical issue about SiO 2-xF x is its low resistance to moisture which causes the dielectric constant of the film to increase with time. In this work, N 2O and NH 3 plasma post-treatments are applied to as-deposited SiO 2-xF x films. It has been observed that NH 3 plasma post-treatments of SiO 2-xF x are quite efficient at blocking moisture. The dielectric constant and stress values of the SiO 2-xF x films after the N 2O and NH 3 plasma post-treatments are very stable. The disadvantage of N 2O plasma post-treatment is that the dielectric constant of the SiO 2-xF x film increases from 3.21 to 3.6 due to fluorine desorption from the SiO 2-xF x network. On the other hand, NH 3 plasma post-treatment is more efficient at blocking moisture and keeping the low dielectric constant unchanged due to surface nitridation of the SiO 2-xF x film.