AlGaN/GaN HEMT grown on large size silicon substrates by MOVPE capped with in-situ deposited Si3N4

ABSTRACTWe have used 2.0-μsec microwave pulses at a frequency of 2.856 GHz to rapidly heat thin amorphous yttrium-barium-copper-oxide (YBCO) films deposited onto silicon substrates. The samples were irradiated inside a WR-284 waveguide by single-pass TE10 pulses in a traveling wave geometry. X-ray diffractometry studies show that an amorphous-to-crystalline phase transition occurs for incident pulse powers exceeding about 6 MW, in which case the amorphous YBCO layer is converted to Y2BaCuO5. Microscopy of the irradiated film reveals that the phase transition is brought about by melting of the YBCO precursor film and crystallization of the molten layer upon solidification. Time-resolved in situ experiments of the microwave reflectivity (R) and transmissivity (T) show that there is an abrupt change in R for microwave pulse powers exceeding the melt threshold, so that measurements of R and T can be used to monitor the onset of surface melting.

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Innenrücktitelbild: In Situ Synthesis of Self-Assembled Gold Nanoparticles on Glass or Silicon Substrates through Reactive Inkjet Printing (Angew. Chem. 2/2014)

Angewandte Chemie ◽

10.1002/ange.201310429 ◽

2013 ◽

Vol 126 (2) ◽

pp. 611-611

Author(s):

Mutalifu Abulikemu ◽

Eman Husni Da'as ◽

Hanna Haverinen ◽

Dongkyu Cha ◽

Mohammad Azad Malik ◽

...

Keyword(s):

Gold Nanoparticles ◽

Inkjet Printing ◽

In Situ Synthesis ◽

Silicon Substrates ◽

Self Assembled

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Silicon carbide emitter diodes by LPCVD (low-pressure chemical vapour deposition) using di-tert-butylsilane

Canadian Journal of Physics ◽

10.1139/p92-151 ◽

1992 ◽

Vol 70 (10-11) ◽

pp. 946-948

Author(s):

S. B. Hewitt ◽

S.-P. Tay ◽

N. G. Tarr ◽

A. R. Boothroyd

Keyword(s):

Chemical Vapour Deposition ◽

Vapour Deposition ◽

Chemical Vapour ◽

Low Pressure ◽

Silicon Substrates ◽

Phosphorus Doping ◽

Forward Current ◽

Pressure Chemical ◽

Sic Films

Stoichiometric SiC films formed by low-pressure chemical vapour deposition from a di-tert-butylsilane source with in situ phosphorus doping from tert-butylphosphine were used as emitters in heterojunction diodes fabricated on lightly doped silicon substrates. Diode characteristics are nearly ideal, with forward current dominated by injection-diffusion in the silicon substrate.

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Kinetics of Pt Silicide Formation Studied by Spectral Ellipsometry

MRS Proceedings ◽

10.1557/proc-470-259 ◽

1997 ◽

Vol 470 ◽

Cited By ~ 2

Author(s):

R. Schwarz ◽

A. Dittrich ◽

S. M. Zhou ◽

M. Hundhausen ◽

L. Ley ◽

...

Keyword(s):

Activation Energy ◽

Crystalline Silicon ◽

Silicon Substrates ◽

Silicide Formation ◽

Spectral Ellipsometry ◽

Step Process ◽

Depth Profiles ◽

Ellipsometric Angle ◽

Kinetics Of

ABSTRACTSuicide formation during thermal annealing of thin Pt layers deposited by evaporation onto crystalline silicon substrates was studied by in-situ spectral ellipsometry. As was shown in an earlier study, Pt suicide is formed in a two-step process with intermediate stages of Pt2Si and PtSi at temperatures of about 190 and 240 °C, respectively. We observed a shift of about 15 °C of the di- and monosilicide formation, when the anneal rate was lowered from 3 to 1 K/min. The analysis of the reaction kinetics using the normalized ellipsometric angle δ yields a good fit to the data for different anneal rates with an activation energy of (1.6 ± 0.2) eV. The underlying model of suicide formation through a multilayer system was checked with depth profiles and compositional information obtained from Rutherford Backscattering.

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In‐Situ Fabrication of YBa2Cu3O7‐x Superconducting Thin Films Directly on Silicon Substrates with Tc0 > 77K

MRS Proceedings ◽

10.1557/proc-169-481 ◽

1989 ◽

Vol 169 ◽

Author(s):

C. B. Lee ◽

R. K. Singh ◽

S. Sharan ◽

A. K. Singh ◽

P. Tiwari ◽

...

Keyword(s):

Thin Films ◽

Laser Pulses ◽

Superconducting Film ◽

Laser Evaporation ◽

Silicon Substrates ◽

Superconducting Thin Films ◽

Si Substrates ◽

In Situ Fabrication ◽

Substrate Temperatures

AbstractWe report in‐situ fabrication of c‐axis textured YBa2Cu3O7‐x superconducting thin films with Tco > 77K on unbuffered silicon substrates by the biased pulsed laser evaporation (PLE) technique in the temperature range of 550‐650°C. At substrate temperatures below 550°C, no c‐axis texturing of the superconducting film was observed. The YBa2Cu3O7‐x superconducting films were fabricated by ablating a bulk YBa2Cu3O7 target by a XeCl excimer laser (λ = 308 nm, τ = 45 × 10‐9 sec) in a chamber maintained at an oxygen pressure of 0.2 torr . The thickness of the films was varied from 0.3 to 0.5 nm depending on the number of laser pulses. Extensive diffusion was observed in thin films deposited at substrate temperatures above 550°C. However, microstructurally, with increase in the substrate temperature the films exhibited larger grain size and greater degree of c‐axis texturing (measured by the ratio of the (005) and (110) X‐ray diffraction peaks). This was found to give rise to better superconducting properties with Tco exceeding 77 K for YBa2Cu3O7‐x films deposited on Si substrates at 650°C.

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Comparison Between In-situ Annealing and External Annealing For Barium Ferrite Thin Films Made by RF Magnetron Sputtering

MRS Proceedings ◽

10.1557/proc-875-o4.22 ◽

2005 ◽

Vol 875 ◽

Author(s):

A. R. Abuzir ◽

W. J. Yeh

Keyword(s):

Thin Films ◽

Magnetron Sputtering ◽

Saturation Magnetization ◽

Barium Ferrite ◽

Rf Magnetron Sputtering ◽

Silicon Substrates ◽

Axis Orientation ◽

Average Value ◽

Ferrite Thin Films

AbstractDue to their large magnetic anisotropy perpendicular to the film plane, barium ferrite thick films (BaFe12O19, or BaM) with c-axis orientation are attractive candidates for microwave applications [1,2]. Barium ferrite thin films on silicon substrates without under layer have been deposited under various conditions by RF magnetron sputtering. The structure of the as-grown films is amorphous. External annealing in air has been done at 950°C for ten minutes to crystallize the films. C-axis oriented thin films with squareness of about 0.87 and coercivity of about 3.8KOe are obtained.Thick BaM films with c-axis orientation are difficult to achieve with one single deposition. Multilayer technique looks promising to grow thick films [3]. The external annealing process is difficult to incorporate with the multilayer procedure. An in-situ annealing procedure has been developed to obtain films, which can be used as the basic component for future multilayer deposition. Barium ferrites are first magnetron sputtered on bare silicon substrates in Ar + O2 atmosphere at substrate temperature of 500-600°C, the deposition pressure was kept about 0.008 torr. After the deposition, the temperature of the substrate is immediately increased to about 860°C for ten minutes in 140 torr of argon (80%) and oxygen (20%) mixture of gas, which was introduced into the chamber without breaking the vacuum. With the in-situ process, c-axis oriented thin films of 0.88 squareness and coercivity value of about 4.3KOe are obtained.Both annealing methods seem to have the similar effect on the perpendicular squareness and coercivity at various film thicknesses. The average value of the saturation magnetization Ms obtained from the in-situ annealing using multilayer technique is higher than that of the external one. We have grown films up to 1.0 micron thickness using the multilayer technique, in which three layers of 0.3 μm thickness each are deposited until the final thickness is reached. After the deposition of each layer, it was in-situ annealed before starting the deposition of the next layer. With the multilayer technique, coercivity of about 3.5 KOe and average value of the saturation magnetization Ms of about 4.0 K Gauss is obtained.

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The Anomalous Influence of Polyelectrolyte Concentration on the Deposition and Nanostructure of Poly(ethyleneimine)/Poly(acrylic acid) Multilayers

Molecules ◽

10.3390/molecules24112141 ◽

2019 ◽

Vol 24 (11) ◽

pp. 2141 ◽

Cited By ~ 3

Author(s):

Martin Müller

Keyword(s):

Acrylic Acid ◽

Attenuated Total Reflection ◽

Silicon Substrates ◽

Acid Base ◽

Exponential Relationship ◽

Individual Adsorption ◽

The Individual ◽

Poly Acrylic Acid

The deposition and nanostructure of polyelectrolyte (PEL) multilayers (PEMs) of branched poly(ethyleneimine)/poly(acrylic acid) (PEI/PAA) onto silicon substrates was studied in terms of the dependence of pH and the PEL concentration (cPEL) in the individual adsorption steps z. Both a commercial automatic dipping device and a homebuilt automatic stream coating device (flow cell) were used. Gravimetry, SFM, transmission (TRANS) and in situ attenuated total reflection (ATR) FTIR spectroscopy were used for the quantitative determination of the adsorbed amount, thickness, chemical composition and morphology of deposited PEMs, respectively. Firstly, the combination of pH = 10 for PEI and pH = 4 for PAA, where both PEL were predominantly in the neutral state, resulted in an extraordinarily high PEM deposition, while pH combinations, where one PEL component was charged, resulted in a significantly lower PEM deposition. This was attributed to both PEL conformation effects and acid/base interactions between basic PEI and acidic PAA. Secondly, for that pH combination an exponential relationship between PEM thickness and adsorption step z was found. Thirdly, based on the results of three independent methods, the course of the deposited amount of a PEM-10 (z = 10) versus cPEL in the range 0.001 to 0.015 M at pH = 10/4 was non-monotonous showing a pronounced maximum at cPEL = 0.005 M. Analogously, for cPEL = 0.005 M a maximum of roughness and structure size was found. Fourthly, related to that finding, in situ ATR-FTIR measurements gave evidence for the release of outermost located PEI upon PAA immersion (even step) and of outermost PAA upon PEI immersion (odd step) under formation of PEL complexes in solution. These studies help us to prepare PEL-based films with a defined thickness and morphology for interaction with biofluids in the biomedical and food fields.

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Autonomous and In Situ Ocean Environmental Monitoring on Optofluidic Platform

Micromachines ◽

10.3390/mi11010069 ◽

2020 ◽

Vol 11 (1) ◽

pp. 69 ◽

Cited By ~ 1

Author(s):

Fang Wang ◽

Jiaomeng Zhu ◽

Longfei Chen ◽

Yunfeng Zuo ◽

Xuejia Hu ◽

...

Keyword(s):

Environmental Monitoring ◽

Chemical Elements ◽

Biogeochemical Cycles ◽

Chemical Parameters ◽

Advantages And Disadvantages ◽

Large Size ◽

High Power Consumption ◽

Marine Disasters ◽

Ocean Monitoring

Determining the distributions and variations of chemical elements in oceans has significant meanings for understanding the biogeochemical cycles, evaluating seawater pollution, and forecasting the occurrence of marine disasters. The primary chemical parameters of ocean monitoring include nutrients, pH, dissolved oxygen (DO), and heavy metals. At present, ocean monitoring mainly relies on laboratory analysis, which is hindered in applications due to its large size, high power consumption, and low representative and time-sensitive detection results. By integrating photonics and microfluidics into one chip, optofluidics brings new opportunities to develop portable microsystems for ocean monitoring. Optofluidic platforms have advantages in respect of size, cost, timeliness, and parallel processing of samples compared with traditional instruments. This review describes the applications of optofluidic platforms on autonomous and in situ ocean environmental monitoring, with an emphasis on their principles, sensing properties, advantages, and disadvantages. Predictably, autonomous and in situ systems based on optofluidic platforms will have important applications in ocean environmental monitoring.

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Identification of Plastic Type and Surface Roughness of Film-Type Plastics in Water Using Kramers–Kronig Analysis

Chemosensors ◽

10.3390/chemosensors8040088 ◽

2020 ◽

Vol 8 (4) ◽

pp. 88

Author(s):

Boniphace Elphace Kanyathare ◽

Benjamin Asamoah ◽

Muhammad Umair Ishaq ◽

James Amoani ◽

Jukka Räty ◽

...

Keyword(s):

Surface Roughness ◽

Light Scattering ◽

Optical Detection ◽

Nir Spectroscopy ◽

Water Bodies ◽

Complex Environment ◽

Large Size ◽

Film Type ◽

Plastic Type

The knowledge of the plastic type, thickness, and the nature of the surface is important towards the monitoring of microplastic pollution in water bodies, especially when vis-NIR spectroscopy is utilized. Factors such as complex environment and surface roughness induced-light scattering of the probing light limit the optical detection of these parameters in in-situ measurements, however. In this paper, a novel application of Kramers–Kronig analysis was exploited to identify both smooth and rough film-type macroplastics with unknown thickness. This method is particularly useful in the in-situ identification of unknown film-like macroplastics; although the sample is large, the ratio function is detected from an area that corresponds to the size of a MP. Therefore, it can be applied for the case of large size MPs. The validity of the method was demonstrated using transmittance data for smooth and roughened plastics given in Kanyathare et al., 2020.

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