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

Abstract

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 3.2×1010 (cm−2 eV−1), making these films a viable high-k dielectric alternative to SiO2 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.

Simulation and Fabrication of HfO2 Thin Films Passivating Si from a Numerical Computer and Remote Plasma ALD

“…The interface charge density (D it ) was calculated from the conductance-voltage curves using the expression [7] …”