APL Photonics (Jan 2024)

Fabrication of gallium nitride waveguide resonators by high-power impulse magnetron sputtering at room temperature

  • Shih-Hsin Wu,
  • Zhi-Guang Chen,
  • Hung-Sheng Liu,
  • Sheng-Hui Chen,
  • Pei-Hsun Wang

DOI
https://doi.org/10.1063/5.0169455
Journal volume & issue
Vol. 9, no. 1
pp. 016106 – 016106-10

Abstract

Read online

In this work, we demonstrate gallium nitride (GaN) waveguide resonators by sputtering amorphous GaN films on the silicon-based substrate. With the aid of high-power impulse magnetron sputtering (HiPIMS), high-quality, high-deposition-rate, and high-flatness GaN films can be deposited directly onto the silicon substrate with a 4 μm buried oxide layer at room temperature. Waveguide resonators with a quality factor of up to 4 × 104 are demonstrated, and closely critical coupling is achieved at a 0.2 μm gap by optimizing the gap sizes, showing a high extinction ratio of waveguide resonators at ≈24 dB. The fabrication process of HiPIMS-GaN waveguide resonators utilizes CMOS-compatible techniques and operates at a low thermal budget. Compared to conventional GaN films fabricated using metal-organic chemical vapor deposition, this study offers the potential to produce low-cost GaN waveguides on amorphous substrates and realize integrated GaN photonics in optical communication, nonlinear photonics, and quantum photonics by high-quality HiPIMS films.