Growth of Crystalline TiO₂by Plasma Enhanced Chemical Vapor Deposition

Abstract

TiO 2 thin films in the form of anatase have been prepared by plasma enhanced chemical vapor deposition (PECVD) at 523 K as the substrate temperature and a low working pressure. The study of the microstructure and texture of the films at different stages of deposition show that their growth follows the Kolmogorov's model developed to describe the evolution of crystalline films from a saturated homogeneous medium. An additional characteristic feature of the growth process by PECVD is the formation of different crystalline domains, particularly at low deposition rates. The effects of this parameter and of the characteristics of the substrate on the growing process are also addressed.

Supported plasma-made 1D heterostructures: perspectives and applications

“…Thus, for example, either columnar or homogeneous TiO 2 thin films can be obtained by using pure O 2 or a mixture Ar+O 2 as plasma gas, respectively [55][56][57]. The formation of homogeneous thin film microstructures by PECVD has been associated with a growing mechanism where surface diffusion of ad-species is the controlling process [55][56][57], while the columnar growth has been related with the existence of shadowing effects and a high sticking coefficient of the ad-species coming from the plasma [55,56,60]. In connection with this columnar growth of thin films, it has been realized that in PECVD processes the particles arrive with a wide distribution of incoming angles and that the actual angular distribution is a key factor in determining the microstructure developed by the films [58,59].…”

“…shown that the thin film microstructure is affected not only by shadowing, diffusion or other similar processes, but mainly by the dynamics of formation of crystallites [60].…”

“…Different processes can be tentatively proposed to account for such enhancement in the crystal development: i) a fast crystal development fostered by the crystalline surface of the metal substrate at the very first steps of the crystal growth, i.e. at the nucleation stage [60] and ii) a possible catalytic effect on the growth driven by the metal layer. As we will see in the next section this latter hypothesis must be discarded.…”

Atomic layer deposition of nano-TiO_2 thin films with enhanced biocompatibility and antimicrobial activity for orthopedic implants

“…[21][22][23][24][25][26] In selecting an appropriate deposition technology for this specific application, several criteria have to be considered such as coating morphology, deposition rate and coverage, interfacial quality, and industrial applicability. Among these methods, the ALD process is based on the sequential use of self-terminating surface reactions, which is perfect for the deposition of metal oxide layers with atomic layer control on geometrical nanostructures with high aspect ratios.…”

Plasma assisted deposition of single and multistacked TiO2 hierarchical nanotube photoanodes

“…19 It is important to address that the temperature required for the formation of the anatase layer (250 ºC) is close to the sublimation temperature of the H 2 PC small-molecule. Therefore, the direct deposition of the TiO 2 at 250 ºC on the ONWs used as 1D scaffolds would eventually lead to their sublimation and evacuation.…”