Conductivity of Titanium Nitride Thin Films

(Conductivity of Titanium Nitride Thin Films)

Various studies have been conducted to evaluate the electrical and optical properties of titanium nitride (TiN) thin films. The most common synthesis method of TiN films is chemical vapor deposition (CVD). In this process, a metallic titanium powder is heated to a high temperature in a nitrogen gas stream. The reaction product is then sinterd to form the final item.

The conductivity of TiN is generally estimated by four-point probe technique. However, the actual conductivity of TiN depends on the stoichiometry, growth process and post-growth oxidation.

During the growth process of TiN, residual oxygen and chlorine can play an important role in the growth of the material. In addition, post-growth oxidation can also alter the TiN optical performance. The optical reflectivity of TiN at normal incidence varies significantly depending on the stoichiometry, density, growth process and post-growth oxidation. In this study, X and Y profiles of TiN films were mapped using interferometric confocal microscopy.

The optical reflectivity of TiN at normal incident angles is mainly dependent on the dielectric losses. In the n-p conduction band, the N-p electrons are dominant and the wide interband absorption originates from states between 2.5 and 5.5 eV below the Fermi level.

In the d(t2g) conduction band, the N-p-Ti-d(t2g) transition is observed. This transition is in accordance with the selection rules for photonic excitation. The mean free path of the conduction electrons is determined by the grain size.

It is believed that TiN has similar properties to transparent conduction oxides such as zinc oxide. Thus, it is possible that TiN could serve as a good metallization material in Si technology.

(Conductivity of Titanium Nitride Thin Films)