Optical properties of amorphous hydrogenated carbon films: A spectroscopic ellipsometry study

1987 ◽  
Vol 2 (5) ◽  
pp. 645-647 ◽  
Author(s):  
Shuhan Lin ◽  
Shuguang Chen
Keyword(s):  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Carbon Films ◽  
Index Of Refraction ◽  
The Real ◽  
Complex Index ◽  
Tentative Explanation ◽  
Amorphous Hydrogenated Carbon ◽  
Ellipsometry Data ◽  
Complex Index Of Refraction

Optical properties of plasma-deposited amorphous hydrogenated carbon films were studied by spectroscopic ellipsometry. From the ellipsometry data, the real and imaginary parts, n and k, of the complex index of refraction of the film have been deduced for photon energies between 2.0 and 4.0 eV for as-grown as well as for thermally annealed films. Here n and k showed considerable variation with subsequent annealing, even under 400°C. A tentative explanation of the results is proposed.

Experimental Techniques

2006 ◽  
Author(s):  
Michael E. Thomas
Keyword(s):  
Absorption Coefficient ◽  
Spectral Response ◽  
Broad Band ◽  
Index Of Refraction ◽  
Experimental Techniques ◽  
The Real ◽  
Complex Index ◽  
Optical Propagation ◽  
Bulk Absorption ◽  
Complex Index Of Refraction

This chapter presents basic experimental techniques and various apparatus for measuring the complex index of refraction and related quantities. Generally, measurements of transmittance, reflectance, and emittance are made using spectrometers or lasers. Other important techniques, which measure directly the real refractive index, n, the absorption coefficient, βabs , and the scattering coefficient, βsca, such as interferometry, ellipsometers, calorimetry, and scatterometers, are also introduced. Ultimately, experimental procedures must be taught in the laboratory. Thus, devoting only one chapter to experimental technique and five to theory is not indicative of the importance of this fundamental topic. By discussing the measurement of basic optical parameters, it is intended that the concepts developed in the first five chapters will be reinforced. All of the theoretical models developed in the previous chapters contain measurable parameters. Basic theory often helps guide the design of a good experiment. Once data is available, it can be used to check the assumptions of the theory. This interplay between experiment and theory is an essential part of definitive work. The chapter has two main parts; the first covers measurements of the real and imaginary parts of the complex index of refraction and the second covers measurements of scattering. As established in Chapter 2, the characterization of bulk absorption mechanisms on optical propagation is accomplished by the complex index of refraction. Considerable effort was expended in Chapters 3, 4, and 5 to obtain models of the complex index. Thus, at this point, we wish to find ways to experimentally measure the complex index of refraction for various media. The broad-band spectral response of a medium is commonly measured by a spectrometer. There are two main types of spectrometers, dispersive and interferometric. Generally, spectrometers make broad-band transmission, emission, and reflection measurements, and therefore indirectly measure, n̄. Interferometric measurements, are the exception. Lasers, which feature narrow-band, high-intensity, highly directional light are often used to complement and calibrate broad-band spectrometer measurements. The highest accuracy measurements of the absorption coefficient are obtainable by laser techniques, which can directly measure the components of the complex index.

scholarly journals Optical properties of humic-like substances (HULIS) in biomass-burning aerosols

2006 ◽  
Vol 6 (11) ◽  
pp. 3563-3570 ◽  
Author(s):  
A. Hoffer ◽  
A. Gelencsér ◽  
P. Guyon ◽  
G. Kiss ◽  
O. Schmid ◽  
...  
Keyword(s):  
Optical Properties ◽  
Absorption Coefficient ◽  
Biomass Burning ◽  
Light Absorption ◽  
Fine Fraction ◽  
Solar Spectrum ◽  
Index Of Refraction ◽  
Complex Index ◽  
532 Nm ◽  
Complex Index Of Refraction

Abstract. We present here the optical properties of humic-like substances (HULIS) isolated from the fine fraction of biomass-burning aerosol collected in the Amazon basin during the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate) experiment in September 2002. From the isolated HULIS, aerosol particles were generated and their scattering and absorption coefficients measured. The size distribution and mass of the particles were also recorded. The value of the index of refraction was derived from "closure" calculations based on particle size, scattering and absorption measurements. On average, the complex index of refraction at 532 nm of HULIS collected during day and nighttime was 1.65–0.0019i and 1.69–0.0016i, respectively. In addition, the imaginary part of the complex index of refraction was calculated using the measured absorption coefficient of the bulk HULIS. The mass absorption coefficient of the HULIS at 532 nm was found to be quite low (0.031 and 0.029 m2 g−1 for the day and night samples, respectively). However, due to the high absorption Ångström exponent (6–7) of HULIS, the specific absorption increases substantially towards shorter wavelengths (~2–3 m2 g−1 at 300 nm), causing a relatively high (up to 50%) contribution to the light absorption of our Amazonian aerosol at 300 nm. For the relative contribution of HULIS to light absorption in the entire solar spectrum, lower values (6.4–8.6%) are obtained, but those are still not negligible.

scholarly journals Optical properties of humic-like substances (HULIS) in biomass-burning aerosols

2005 ◽  
Vol 5 (4) ◽  
pp. 7341-7360 ◽  
Author(s):  
A. Hoffer ◽  
A. Gelencsér ◽  
P. Guyon ◽  
G. Kiss ◽  
O. Schmid ◽  
...  
Keyword(s):  
Optical Properties ◽  
Absorption Coefficient ◽  
Biomass Burning ◽  
Amazon Basin ◽  
Fine Fraction ◽  
Solar Spectrum ◽  
Index Of Refraction ◽  
Complex Index ◽  
532 Nm ◽  
Complex Index Of Refraction

Abstract. We present here the optical properties of humic-like substances (HULIS) isolated from the fine fraction of biomass burning aerosol collected in the Amazon basin during the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate) experiment in September 2002. From the isolated HULIS, aerosol particles were generated and their scattering and absorption coefficients measured. The size distribution and mass of the particles were also recorded. The value of the index of refraction was derived from "closure'' calculations based on particle size, scattering and absorption measurements. On average, the complex index of refraction at 532 nm of HULIS collected during day and nighttime was 1.65–0.00187i and 1.69–0.00163i, respectively. In addition, the imaginary part of the complex index of refraction was calculated using the measured absorption coefficient of the bulk HULIS. The mass absorption coefficient of the HULIS was found to be quite low at 532 nm (0.031 and 0.029 m2g−1 for the day and night samples, respectively). However, due to the high Ångström exponent of HULIS (6–7) the specific absorption increases substantially towards shorter wavelengths m2g−1 at 300 nm), causing a relatively high (up to 50%) contribution to the absorption at this wavelength. For the relative contribution of HULIS to light absorption in the entire solar spectrum, lower values (6.4–8.6%) are obtained, but those are still not negligible.

Optical Properties of Metal Films and Their Silicides

1994 ◽  
Vol 337 ◽  
Author(s):  
M. Simard-Normandin ◽  
A. Naem ◽  
M. Saran
Keyword(s):  
Optical Properties ◽  
Optical Constants ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Metal Films ◽  
Index Of Refraction ◽  
Contact Method ◽  
Microelectronic Fabrication ◽  
Silicide Growth ◽  
Complex Index Of Refraction

ABSTRACTSilicides are used widely in microelectronic fabrication, yet there are very little data available regarding their optical constants at most wavelengths, and specifically at those of interest to G-line and I-line lithography. We have studied extensively the optical properties of Ti, Co, as metal films and as silicide films formed at various temperatures, and of CVD (chemical vapour deposition) W. Using spectroscopic ellipsometry at two angles of incidence, we have calculated the complex index of refraction N = (n, k) of these films every 10nm at 68 wavelengths between 230 and 900nm. These data are necessary to model accurately the reflectivity of wafers to study the effects of various thermal and surface treatments on silicide growth and to set exposure times for lithography. They also allow the use of reflectivity vs X as a non-contact method to map film thicknesses across wafers within the patterned devices themselves.

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