17 April 2000 Multispectral reflectance-mode fiber optic deposition rate monitor
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Proceedings Volume 3938, Light-Emitting Diodes: Research, Manufacturing, and Applications IV; (2000) https://doi.org/10.1117/12.382831
Event: Symposium on Integrated Optoelectronics, 2000, San Jose, CA, United States
Abstract
We have developed and demonstrated a reflection-mode optical fiber-based instrument for in situ monitoring and feedback control of thin film dielectric deposition processes. The instrument operates in single-wavelength or multi-wavelength mode. One end of the fiber is placed in the deposition zone, close to the samples being coated. Single or multi-wavelength light is sent down the fiber and the reflected light from the end being coated is analyzed for intensity vs. wavelength. The fiber end being coated features an easily replaced tip to prevent loss of resolution when the coating becomes too thick. For processes in which the index of refraction or composition of the thin films is fixed, the less expensive single wavelength instrument is sufficient and measures thickness of the films by counting interference fringes. For processes in which film composition or index of refraction are variable, we use a white light source and compact spectrograph to measure reflectance vs. wavelength. For critical applications like diode laser facet coating where yield loss is significant cost driver, this monitor measures the thickness and index of refraction of single and multi-layer thin films as they are deposited. More importantly, it measures the critical parameter of interest: reflectance at the actual laser emission wavelength. This instrument replaces quartz crystal oscillators and other, more complex instruments.
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James T. Daly, James T. Daly, John A. Wollam, John A. Wollam, Fei Luo, Fei Luo, Theodore F. Morse, Theodore F. Morse, Andreas Kussmaul, Andreas Kussmaul, Dan Pulver, Dan Pulver, } "Multispectral reflectance-mode fiber optic deposition rate monitor", Proc. SPIE 3938, Light-Emitting Diodes: Research, Manufacturing, and Applications IV, (17 April 2000); doi: 10.1117/12.382831; https://doi.org/10.1117/12.382831
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