Improvements of Fourier transform phase-modulated ellipsometry

Vallon, S.; Compain, Eric; Drévillon, B.

doi:10.1063/1.1145492

Cited by 25 publications

(6 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…10 The insoluble fraction in tetrahydrofurane ͑THF͒ was determined as follows. Both ellipsometers use a photoelastic modulator to achieve fast modulation of the signal ͑50 kHz in the UV-visible, 37 kHz in the IR͒.…”

Section: Methodsmentioning

confidence: 99%

Argon plasma treatment of polycarbonate: In situ spectroellipsometry study and polymer characterizations

Vallon¹,

Drévillon²,

Poncin‐Epaillard³

et al. 1996

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

Self Cite

View full text Add to dashboard Cite

The influence of argon plasma on polycarbonate ͑PC͒ was studied in terms of structural changes, reaction mechanisms, and adhesion. In situ ultraviolet-visible ellipsometry reveals formation of a surface layer with a higher refractive index than the untreated polymer. The increase in the refractive index is attributed to polymer densification, which in turn is attributed to crosslinking. However a decrease in the average molecular weight is also observed, and two populations of macromolecules of different sizes are detected by light scattering measurements, revealing a competition between crosslinking and degradation. The reaction mechanisms are investigated using nuclear magnetic resonance and in situ infrared ellipsometry. Degradation is caused by carbonate bond breaking, whereas crosslinking seems to be related to a decrease in methyl groups. In addition, an increase in surface acidity is detected by contact angle measurements and is attributed to photo-Fries rearrangements producing phenolic groups. The adhesion of a 1-m-thick silica layer on PC is evaluated by the microscratch test, and its enhancement by argon plasma pretreatment is analyzed.

show abstract

Section: Methodsmentioning

confidence: 99%

Argon plasma treatment of polycarbonate: In situ spectroellipsometry study and polymer characterizations

Vallon¹,

Drévillon²,

Poncin‐Epaillard³

et al. 1996

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

Self Cite

View full text Add to dashboard Cite

show abstract

“…[1][2][3][4] The technique has been applied to a number of materials problems, including: the transverseoptic ͑TO͒ phonon absorption and doping concentration in n-type GaAs, 5 one-and two-phonon absorption in LiF, 6,7 graded carrier concentration profiles in implanted and epitaxial silicon, 8,9 and epitaxial and bulk-doping concentrations for In x GaAs 1Ϫx Sb epilayers on GaSb. 10 IR-SE has been applied to the study of strong phonon anisotropy in bulk ␣-SiO 2 and ␣-Al 2 O 3 by Humlíček and Röseler.…”

Section: Introductionmentioning

confidence: 99%

Carrier concentration and lattice absorption in bulk and epitaxial silicon carbide determined using infrared ellipsometry

et al. 1999

View full text Add to dashboard Cite

Wetteroth, T.; Wilson, S. R.; and Powell, Adrian R., "Carrier concentration and lattice absorption in bulk and epitaxial silicon carbide determined using infrared ellipsometry" (1999 Carrier concentration and lattice absorption in bulk and epitaxial silicon carbide determined using infrared ellipsometry We have measured the dielectric function of bulk nitrogen-doped 4H and 6H SiC substrates from 700 to 4000 cm Ϫ1 using Fourier-transform infrared spectroscopic ellipsometry. Photon absorption by transverse optical phonons produces a strong reststrahlen band between 797 and 1000 cm Ϫ1 with the effects of phonon anisotropy being observed in the region of the longitudinal phonon energy ͑960 to 100 cm Ϫ1 ͒. The shape of this band is influenced by plasma oscillations of free electrons, which we describe with a classical Drude equation. For the 6H-SiC samples, we modify the Drude equation to account for the strong effective mass anisotropy. Detailed numerical regression analysis yields the free-electron concentrations, which range from 7ϫ10 17 to 10 19 cm Ϫ3 , in good agreement with electrical and secondary ion mass spectrometry measurements.Finally, we observe the Berreman effect near the longitudinal optical phonon energy in nϪ/nϩ homoepitaxial 4H SiC and hydrogen implanted samples, and we are able to determine the thickness of these surface layers.

show abstract

“…Phase modulated apparatus is also involved in the ellipsometric measurement. The ellipsometer based on the use of a photoelastic modulator (PEM) is the most prevalent configuration; it has a typical modulation frequency of 50 kHz with no moving parts [11][12][13]. For single spot measurement, one can employ either lock-in amplifiers or the Fourier analysis technique to obtain the ellipsometric parameters in near real-time, but this approach is not applicable for a two-dimensional measurement, because the modulation frequency of the PEM is too high to compare it with the exposure times of the CCD camera.…”

Section: Introductionmentioning

confidence: 99%

Photoelastic Modulated Imaging Ellipsometry

Han¹,

Chao²,

Tsai³

2017

Ellipsometry - Principles and Techniques for Materials Characterization

View full text Add to dashboard Cite

Photoelastic modulator (PEM)-based ellipsometry employed either lock-in amplifiers or the Fourier analysis technique to obtain the ellipsometric parameters almost in real-time that makes the system with a feature of fast measurement speed, higher stability, and sensitivity at small retardations. Since the PEM modulation frequency is too high to compare it with the exposure time of the camera, photoelastic modulator-based approach is not applicable for a two-dimensional ellipsometric measurement. Here, we represent a novel technique that coordinates with the light pulses and PEM modulation that can freeze the time-varied signals. Thus, two-dimensional ellipsometric parameters can be obtained within few seconds. In addition to ellipsometric measurement, this approach also can be extended to other imaging polarimetry measurements, such as Stokes parameters and Mueller matrix. Moreover, since the chromatic dispersion of birefringence was also a significant issue in the polarization modulation systems, we proposed an equivalent phase retardation technique to deal with this issue. This technique was confirmed by a dual wavelength measurement result without changing the optical configuration of the system. The concept and the theory of this system were indicated in the preceding section, and the passage below described some calibration issues for the photoelastic modulator. Some measurement results were revealed in the final part of this chapter.

show abstract

Improvements of Fourier transform phase-modulated ellipsometry

Cited by 25 publications

References 9 publications

Argon plasma treatment of polycarbonate: In situ spectroellipsometry study and polymer characterizations

Argon plasma treatment of polycarbonate: In situ spectroellipsometry study and polymer characterizations

Carrier concentration and lattice absorption in bulk and epitaxial silicon carbide determined using infrared ellipsometry

Photoelastic Modulated Imaging Ellipsometry

Contact Info

Product

Resources

About