Electrical and optical characterization of SiONC dielectric thin film deposited by polymer-source chemical vapor deposition

• Published in: Journal of applied physics 2007-04, Vol.101 (8), p.084107-084107-5
• Main Authors: Oulachgar, El Hassane, Aktik, Cetin, Scarlete, Mihai, Dostie, Starr, Sowerby, Rob, Gujrathi, Subhash
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.2717607

The electro-optical properties of SiONC dielectric thin films deposited by polymer-source chemical vapor deposition using an organosilane precursor has been investigated as a function of oxygen concentration in the films. SiONC thin films were characterized using capacitance-voltage ( C - V ), conductance-voltage ( G - V ), ellipsometry, and ultraviolet visible (UV-Vis) photospectroscopy. These measurements showed that the electro-optical properties of the films are greatly influenced by the atomic concentration of oxygen. The high frequency C - V measurement revealed a nearly ideal metal-oxide-semiconductor (MOS) structure behavior at high atomic concentration of oxygen (35 at.%). A relative dielectric constant as high as 6 is obtained at 10 kHz for samples with about 5 at.% of oxygen, which corresponds to high- k dielectric material. The interface trap density extracted from G - V measurement using Hill-Coleman method is as low as 3.2 × 10 10 ( cm − 2 eV − 1 ) , making these films a viable high- k dielectric alternative to SiO 2 and SiON in MOS devices. The refractive index measured by ellipsometry at a wavelength of 632.8 nm shows a linear variation with atomic concentration of oxygen from 1.58 to 1.69. The optical energy band gap extracted from UV-Vis absorption spectra was found to vary between 4.40 and 5.25 eV.