AVS 51st International Symposium
    Thin Films Friday Sessions
       Session TF-FrM

Invited Paper TF-FrM2
MultiChannel Mueller Matrix Ellipsometry for In-Situ and Real Time Analysis of Thin Films and Surfaces

Friday, November 19, 2004, 8:40 am, Room 303C

Session: In-Situ/Ex-Situ & Real-Time Monitoring
Presenter: R.W. Collins, University of Toledo
Authors: R.W. Collins, University of Toledo
C. Chen, University of Toledo
I. An, University of Toledo
N.J. Podraza, University of Toledo
Correspondent: Click to Email
A dual rotating compensator multichannel ellipsometer has been applied for real time Mueller matrix spectroscopy (2 to 5 eV) of anisotropic surfaces and thin films. The sequence of optical elements for this instrument is denoted PC@sub 1@SC@sub 2@A, where P, S, and A represent the polarizer, sample, and analyzer. C@sub 1@ and C@sub 2@ represent the first and second compensators that rotate at frequencies of 10 and 6 Hz, respectively, synchronized for a 5:3 ratio. At this ratio, the 2n@omega@ frequencies where n = 1, ..., 8, 10, 11, 13, and 16, and where @omega@/2@pi@ = 2 Hz, are present in the detected irradiance waveform for the most general sample Mueller matrix. The associated 25 experimental dc, cosine, and sine Fourier coefficients are determined for a given pixel of the photodiode array detector by integrating the waveform 36 times per optical cycle. Spectra in the 16 Mueller matrix elements can be determined from spectra in the 25 non-zero coefficients acquired in a single 250 ms optical cycle and from instrument calibration data obtained in advance. In high speed Mueller matrix measurements, this research has focused on weakly anisotropic surfaces and thin films that push the instrument to its limits. These include the (110) Si surface and thin films having an oriented columnar microstructure in which case the weak anisotropic optical response can be over-determined from analyses employing separate 2x2 blocks of the Mueller matrix. As a result, detection of anisotropy is definitive, and the co- and cross-polarization ellipsometric angles @psi@@sub pp@, @psi@@sub ps@, and @psi@@sub sp@ can be determined to within an accuracy of 1 part in 10@super 4@.