Fabrication of smooth silicon optical devices using proton beam writing

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Vol. 269; no. 20; pp. 2448 - 2451
• Main Authors: Teo, E.J., Bettiol, A.A., Xiong, B.Q.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.10.2011
• Subjects: Devices; Diffraction gratings; Disks; Electrochemical etching; Gratings (spectra); Optical devices; Porous silicon; Process parameters; Proton beam writing; Proton beams; Silicon; Silicon photonics; Waveguides; Waveguides; Silicon photonics; Porous silicon; Electrochemical etching; Optical devices; Proton beam writing
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2011.02.015

This work gives a brief review of proton beam writing and electrochemical etching process for the fabrication of smooth optical devices in bulk silicon. Various types of structures such as silicon-on-oxidized porous silicon waveguides, waveguide grating and disk resonators have been produced. Optical characterization has been carried out on the waveguides for both TE and TM polarization using free space coupling at 1.55μm. Various fabrication and processing parameters have been optimized in order to reduce the propagation loss to approximately 1dB/cm. A surface smoothening technique based on controlled oxidation has also been used to achieve an RMS roughness better than 3nm.