Optical monitoring of technological processes for fabrication of thin-film nanostructures

Thisworkillustratesapplicationofthe uniquefiber-optic instrumentationforin situmonitoringofseveral technologicalprocessescommonlyusedinfabricationof semiconducting thin-film nanostructures. This instrumentation is basedonprinciplesoflowcoherenttandeminterferometry, whichdetermineshighsensitivityandprecision in measuring basic technological parameters, such as thickness of forming layers, temperature and bending of the substrate.The probing wavelength = 1.55 m allows carrying out the measurements on majority of substrates for semiconductor technology: Si, SOI, GaAs, InP, GaP, Al2O3, diamond, ZrO2:Y. Monitoring of such processes as MOVPE, MBEandplasmaetchingin various set-ups was realized. The absolute resolution achieved in these experiments was limited only by calibration accuracy and corresponds to 1 at sensitivity of 0.01 . The accuracy limit in estimating the thickness of layers during their growth is 2 nm. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2068

Electrical Isolation Of A Silicon δ-doped Layer In Gaas By Ion Irradiation

The electrical isolation of a n-type δ-doped layer embedded into undoped GaAs was studied using proton or helium ion bombardment. The threshold dose for isolation Dth of the δ-doped layer was found to be ≈2 times higher than that predicted for thick doped layers of similar carrier concentration. The thermal stability of the isolation, i.e., the persistence of sheet resistance Rs at values > 109Ω/□ after subsequent thermal annealing, is limited to temperatures below 400°C. This temperature limit for the thermal stability Tsm is markedly lower than those observed in wider doped layers in which Tsm is ≅650°C. A previously isolated δ-doped layer presents p-type conductivity after annealing at temperatures >600°C . © 1999 American Institute of Physics.751319171919Shubert, E.F., (1990) J. Vac. Sci. Technol. A, 8, p. 2980Daniltsev, V.M., Irin, I.V., Murel, A.V., Khrykin, O.I., Shashkin, V.I., (1994) Inorg. Mater. (Transl. of Neorg. Mater.), 30, p. 948Zrenner, A., Koch, F., Ploog, K., (1987) Inst. Phys. Conf. Ser., 91, p. 171Van Der Pauw, L.J., (1958) Philips Res. Rep., 13, p. 1De Souza, J.P., Danilov, I., Boudinov, H., (1997) J. Appl. Phys., 81, p. 650Ziegler, J.F., Biersack, J.P., Littmark, U., (1985) The Stopping and Range of Ions in Solids, 1. , Pergamon, OxfordDe Souza, J.P., Danilov, I., Boudinov, H., (1998) J. Appl. Phys., 84, p. 4757De Souza, J.P., Danilov, I., Boudinov, H., (1996) Appl. Phys. Lett., 68, p. 535De Souza, J.P., Danilov, I., Boudinov, H., (1998) Radiat. Eff. Defects Solids, 147, p. 109Grandidier, B., Stiévenard, D., Nys, J.P., Wallart, X., (1998) Appl. Phys. Lett., 72, p. 245

The Atmospheric Chemistry Suite (ACS) of Three Spectrometers for the ExoMars 2016 Trace Gas Orbiter

The Atmospheric Chemistry Suite (ACS) package is an element of the Russian contribution to the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission. ACS consists of three separate infrared spectrometers, sharing common mechanical, electrical, and thermal interfaces. This ensemble of spectrometers has been designed and developed in response to the Trace Gas Orbiter mission objectives that specifically address the requirement of high sensitivity instruments to enable the unambiguous detection of trace gases of potential geophysical or biological interest. For this reason, ACS embarks a set of instruments achieving simultaneously very high accuracy (ppt level), very high resolving power (>10,000) and large spectral coverage (0.7 to 17 μm—the visible to thermal infrared range). The near-infrared (NIR) channel is a versatile spectrometer covering the 0.7–1.6 μm spectral range with a resolving power of ∼20,000. NIR employs the combination of an echelle grating with an AOTF (Acousto-Optical Tunable Filter) as diffraction order selector. This channel will be mainly operated in solar occultation and nadir, and can also perform limb observations. The scientific goals of NIR are the measurements of water vapor, aerosols, and dayside or night side airglows. The mid-infrared (MIR) channel is a cross-dispersion echelle instrument dedicated to solar occultation measurements in the 2.2–4.4 μm range. MIR achieves a resolving power of >50,000. It has been designed to accomplish the most sensitive measurements ever of the trace gases present in the Martian atmosphere. The thermal-infrared channel (TIRVIM) is a 2-inch double pendulum Fourier-transform spectrometer encompassing the spectral range of 1.7–17 μm with apodized resolution varying from 0.2 to 1.3 cm−1. TIRVIM is primarily dedicated to profiling temperature from the surface up to ∼60 km and to monitor aerosol abundance in nadir. TIRVIM also has a limb and solar occultation capability. The technical concept of the instrument, its accommodation on the spacecraft, the optical designs as well as some of the calibrations, and the expected performances for its three channels are described

Electrical isolation of a silicon [Delta]-doped layer in GaAs by ion irradiation

The electrical isolation of a n-type d -doped layer embedded into undoped GaAs was studied using proton or helium ion bombardment. The threshold dose for isolation Dth of the d -doped layer was found to be '2 times higher than that predicted for thick doped layers of similar carrier concentration. The thermal stability of the isolation, i.e., the persistence of sheet resistance Rs at values .109V/h after subsequent thermal annealing, is limited to temperatures below 400 °C. This temperature limit for the thermal stability Tsm is markedly lower than those observed in wider doped layers in which Tsm is >650 °C. A previously isolated d -doped layer presents p-type conductivity after annealing at temperatures .600 °C

Electrical isolation of a silicon [Delta]-doped layer in GaAs by ion irradiation

The electrical isolation of a n-type d -doped layer embedded into undoped GaAs was studied using proton or helium ion bombardment. The threshold dose for isolation Dth of the d -doped layer was found to be '2 times higher than that predicted for thick doped layers of similar carrier concentration. The thermal stability of the isolation, i.e., the persistence of sheet resistance Rs at values .109V/h after subsequent thermal annealing, is limited to temperatures below 400 °C. This temperature limit for the thermal stability Tsm is markedly lower than those observed in wider doped layers in which Tsm is >650 °C. A previously isolated d -doped layer presents p-type conductivity after annealing at temperatures .600 °C

Development of hybrid low pressure MSGC neutron detectors

For very high rate and resolution time resolved experiments at next generation pulsed spallation neutron sources like ESS large area hybrid low pressure micro strip gas chamber detectors are being developed. Due to their thin composite converter foil and exponential gas multiplication commencing at the converter surfaces the detectors are free of parallax, and according to detailed modeling the very high transverse and longitudinal localization accuracies in the conversion and gas multiplication processes allow position and time resolutions of 100 m and lt;10 ns FWHM for thermal neutrons, respectively, the latter limited by the transit time through the converter. In the European R amp;D project TECHNI for this detector an advanced delay line readout technology with multi event readout was developed as an economical solution for the majority of applications, which, however, limits the position resolution and rate capability to lt;0.3 mm and 1 2 Mcps, respectively. Therefore, in the successor project DETNI a dedicated ASIC family is being developed for achieving position resolutions of 100 m FWHM and counting rates of 108 cps. This will open up novel applications based on time of flight TOF and single event detection with very high dynamic range, replacing integrating CCD and image plate detectors, e.g. in radiography tomography, TOF Laue diffraction, single crystal diffraction and focusing low Q SANS. In this conference report new results concerning the technical realization of this detector system are reported in conjunction with a brief summary of the detector principle and with reference to earlier result