Surface oxidation of Al masks for deep dry-etch of silica optical waveguides
نویسندگان
چکیده
The surface oxidation of Al metal masks in an oxygen plasma was studied for realizing deep dry-etch of silica optical waveguides. The oxidation efficiency of the plasma was found to depend on mainly substrate bias and plasma power. Net sputtering effect happened when ion bombarding potential exceeds certain critical value. However, suitable ion bombarding energy is of benefit to the oxidation process. There was a saturation thickness of the Al2O3 layer, beyond which the growth rate of Al2O3 films became very low. The saturation thickness increased with the plasma power. According to these growth characteristics, the oxide growth mechanisms were discussed, and suitable plasma conditions were chosen for the surface oxidation of Al metal masks. Under the chosen plasma conditions, a thick Al2O3 layer of ∼6.5 nm was generated in a short time of 2 min. Thus the surface of the Al metal mask could be periodically oxidized during the breaks of the silica etching process to enable much higher SiO2/mask etching selectivity of ∼100:1, in comparison with ∼15/1 obtained without the surface oxidization process. This greatly reduced the required Al mask thickness from over 500 to 100 nm for a deep silica etch of over 5 μm, and leaded to the achievement of high-quality silica waveguides with vertical and very smooth sidewalls. © 2006 Elsevier B.V. All rights reserved. PACS: 52.77; 52.40; 81.15; 81.65; 82.45
منابع مشابه
Formation of plasma induced surface damage in silica glass etching for optical waveguides
Ge, B, P-doped silica glass films are widely used as optical waveguides because of their low losses and inherent compatibility with silica optical fibers. These films were etched by ICP !inductively coupled plasma" with chrome etch masks, which were patterned by reactive ion etching !RIE" using chlorine-based gases. In some cases, the etched surfaces of silica glass were very rough !root-mean s...
متن کاملEtch-free low loss silicon waveguides using hydrogen silsesquioxane oxidation masks.
An etch-free fabrication technique for creating low loss silicon waveguides in the silicon-on-insulator material system is proposed and demonstrated. The approach consists of local oxidation of a silicon-on-insulator chip covered with a e-beam patterned hydrogen silsesquioxane mask. A single oxidation step converts hydrogen silsesquioxane to a glass-like compound and simultaneously defines the ...
متن کاملHigh index contrast polysiloxane waveguides fabricated by dry etching
The authors demonstrate the production of low loss enhanced index contrast waveguides by reactive ion etching of IPGTM polysiloxane thin films. The use of a silica mask and CHF3 /O2 etch gas led to large etch selectivity between the silica and IPGTM of !20 and etch rates of !100 nm /min. This work indicates that compact optical circuits could be successfully fabricated for telecommunication app...
متن کاملDry-etch of As2S3 thin films for optical waveguide fabrication
Plasma etching to As2S3 thin films for optical waveguide fabrication has been studied using a helicon plasma etcher. The etching effects using the processing gases or gas mixtures of O2, Ar, and CF4 were compared. It was found that the O2 plasma had no chemical etching effect to the As2S3, but it could oxidize the surface of the As2S3. The Ar plasma provided a strong ion sputtering effect to th...
متن کاملDeep SiO2 etching with Al and AlN masks for MEMS devices
Silicon oxide-based materials such as quartz and silica are widely used in Microelectromechanical Systems (MEMS). One way to enhance capability of their deep plasma etching is to increase selectivity by the use of hard masks. Though this approach was studied previously, information on the use of hard masks for etching of silicon-oxide based materials on 200 mm substrates is scarce. We present r...
متن کامل