Optimized ICPCVD-Based TiO₂ for Photonics

Area of Science:

• Materials Science
• Optoelectronics
• Thin Film Technology

Background:

• Fabricating low-loss waveguides requires dense, homogeneous thin films with high refractive indices.
• Titanium dioxide (TiO2) is a promising material, but achieving optimal optical properties is challenging.
• Crystallized or amorphous TiO2 layers often exhibit insufficient refractive indices for targeted waveguide applications.

Purpose of the Study:

• To optimize the fabrication of TiO2 films via ICPCVD for low-loss waveguides.
• To investigate the impact of deposition and annealing parameters on TiO2 film properties.
• To achieve an intermediate crystallization state in TiO2 films for enhanced optical performance.

Main Methods:

• Inductively Coupled Plasma Chemical Vapor Deposition (ICPCVD) was used to deposit TiO2 films.
• Systematic variation of plasma power, pressure, deposition time, and annealing temperature.
• Structural, crystalline, and optical properties were analyzed using techniques including Transmission Electron Microscopy (TEM).

Main Results:

• Nanoscale crystallization into the rutile phase occurred during ICPCVD deposition.
• Optimized conditions yielded a refractive index of 2.5 at 630 nm with high film homogeneity.
• Annealing further increased the refractive index to 2.6.
• TEM confirmed nanocrystallization and the presence of both anatase and rutile phases.

Conclusions:

• An intermediate nanoscale crystallization state of TiO2 is optimal for guided optics applications.
• ICPCVD combined with controlled annealing offers a viable method for fabricating high-performance waveguide materials.
• The achieved refractive index and homogeneity meet the stringent requirements for low-loss waveguides.