B.S. 1968
National Taiwan Normal University

M.S. 1970
Wisconsin State University-Superior

Ph.D. 1977
Wesleyan University

　The most important break through in my laboratory was the intensity ratio technique for aligning the azimuths of polarizer and analyzer to the incident plane [12]. In addition to the alignment technique, a three irradiances [11] measurement technique was used to obtain the ellipsometric parameters and azimuth deviation in the measurement, both precisions are comparable to that of commercial system. For in situ/real time measurement, we introduce a photoelastic modulator in the ellipsometric system. After developing a fixed incident angle alignment technique [7], we help NTHU to install a PEM style ellipsometry [Fig. 1] for monitoring the plasma etching process. Besides the ellipsometry, we also put a great effort in developing the Mueller polarimetry. The most recent result was to measure the twisted angle and phase retardation of a TN-LCD. It is my interest to develop a polarization technique to measure the physical properties of a material, such as the complex refractive indices, thin film thickness… I am not limited myself to the isotropic medium, an elliptical anisotropic material is under study.

1. Yu Faye Chao, Kan Yan Lee and Yi De Lin, Analytical solutions of the azimuth deviation of polarizer/analyzer in the Polarizer-Sample-Analyzer ellipsometry, Appl. opt., 45 , 3935-3939, 2006

2. Chien-Yuan Han, Yu-Faye Chao, Photoelastic modulated imaging ellipsometry by stroboscopic illumination technique, Rev. Sci. Instrum., 77, 023017, 2006

3. Kan Yan Lee and Yu Faye Chao, The Ellipsometric Measurements of a Curved Surface, Jpn. J. Appl. Phys. 44 pp.L1015 - L1018, 2005

4. Yu Faye Chao and Kan Yan Lee, Index profile of radial gradient index lens measured by Imaging ellipsometric technique, Jpn. J Appl. Phys. 44 , pp 1111-1114, 2005

5. M. W. Wang, F. H. Tsai and Y. F. Chao, In situ calibration technique for photoelastic modulator in ellipsometry, Thin Solid Films 455-456, pp 78-83, 2004

6. M. W. Wang, Y. F. Chao, K. C. Leou, F. H. Tsai, T. L. Lin, S. S. Chen and Y. W. Liu, Calibrations of phase modulation amplitude of photoelastic modulator, Jpn. J. Appl. Phys. 43 , pp. 827-832, 2004

7. M. W. Wang and Y. F. Chao, Azimuth alignment in photoelastic modulation ellipsometry at a fixed incident angle, Jpn. J. Appl. Phys. 41 , pp. 3981-3986, 2002

8. Y. F. Chao, The intensity ratio alignment technique in photoelastic modulation ellipsometry and polarimetry, SPIE proceeding, 4833 , 317-324, 2002 (invited paper)

9. Y. F. Chao, A. Lin and M. W. Wang, Photoelastic modulation polarimetry and its measurement of Twisted Nematic Liquid Crystal, SPIE proceeding, 4595 , pp 43-51, 2001

10. Y.F. Chao, M.W. Wang and Z. C. Ko, An error evaluation technique for the angle of incidence in a rotating element ellipsometer using a quartz crystal, J. Phys. D. Appl. Phys. 32, 2246-2249, 1999

11. Y. F. Chao, W. C. Lee, C.S. Hung, and J J Lin, A three-intensity technique for polarizer-sample-analyzer photometric ellipsometry and polarimetry, J. Phys. D. Appl. Phys. 31, 1968-1974, 1998

12. Y. F. Chao, C. S. Wei, W. C. Lee, S. C. Lin, and T. S. Chao, Ellipsometric measurements and its Alignment: Using the Intensity ratio technique Jpn. J.Appl. Phys. 34, 5016, 1995

5. Yu-Faye Chao, et. al., An error evaluation technique for incident angle in rotating element ellipsometry, pending 2001/12

　The most important break through in my laboratory was the intensity ratio technique for aligning the azimuths of polarizer and analyzer to the incident plane. In addition to the alignment technique, a three irradiances measurement technique was used to obtain the ellipsometric parameters and azimuth deviation in the measurement, both precisions are comparable to that of commercial systems. For in situ/real time measurement, we introduce a photoelastic modulator in the ellipsometric system. After developing a fixed incident angle alignment technique, we help NTHU to install a PEM style ellipsometry for monitoring the plasma etching process. A SPR enhanced PEM ellipsometry has been implemented to achieve a 25000/s data rate. Two imaging ellipsometry in PSA and PEM have been realized. It is my interest to develop the polarization technique to measure the physical properties of all kind materials.