| dc.description.abstract | Short-wave infrared (SWIR) wavelengths are crucial in communication, sensing, medical, and automotive industries due to their ability to penetrate water, fog, silicon, and biological tissues, and their low scattering and absorption at 1350/1550 nm. Germanium-based materials, with high transparency and low absorption, are ideal for narrowband filters. This study extends applications at near-infrared wavelengths of 850/940 nm by designing high-quality SWIR narrowband filters.
Building on previous research with optimized parameters at 500°C, this experiment reduces the deposition temperature to below 200°C for practical wafer-level applications. Further optimization of power and gas flow rates was conducted. The optical properties were analyzed using UV-IR spectroscopy and Essential Macleod software, and the chemical composition and material properties were examined using FTIR, XPS, SEM, XRD, and AFM. Optimized parameters resulted in high-transmittance SWIR narrowband filters.
The experiment is divided into three parts. First, the process for high-refractive-index materials was optimized by adjusting temperature, power, and hydrogen flow rate, addressing plasma arcing issues. The films achieved a refractive index of 4.095 and an extinction coefficient of 7E-3. Second, the oxygen flow rate was optimized to prevent target poisoning, achieving a refractive index of 1.597 and an extinction coefficient of 4.5E-4. Third, the optimized parameters were used to design narrowband filters at 1350/1550 nm, achieving center wavelength transmittance of 87.9% and 88% with film thicknesses of 2 μm and 2.4 μm.
| en_US |