scholarly journals Internal Friction and Young's Modulus Measurements on SiO2 and Ta2O5 Films Done with an Ultra-High Q Silicon-Wafer Suspension

2015 ◽  
Vol 60 (1) ◽  
pp. 365-370 ◽  
Author(s):  
M. Granata ◽  
L. Balzarini ◽  
J. Degallaix ◽  
V. Dolique ◽  
R. Flaminio ◽  
...  
Keyword(s):  
Thin Films ◽  
Internal Friction ◽  
Silicon Wafer ◽  
Room Temperature ◽  
Suspension System ◽  
Cryogenic Temperatures ◽  
Resonant Frequencies ◽  
High Q ◽  
Key Features ◽  
Q Factors

Abstract In order to study the internal friction of thin films a nodal suspension system called GeNS (Gentle Nodal Suspension) has been developed. The key features of this system are: i) the possibility to use substrates easily available like silicon wafers; ii) extremely low excess losses coming from the suspension system which allows to measure Q factors in excess of 2×108 on 3” diameter wafers; iii) reproducibility of measurements within few percent on mechanical losses and 0.01% on resonant frequencies; iv) absence of clamping; v) the capability to operate at cryogenic temperatures. Measurements at cryogenic temperatures on SiO2 and at room temperature only on Ta2O5 films deposited on silicon are presented.

Size Dependent Electroluminescence from CdSe Nanocrystallites (Quantum Dots)

1994 ◽  
Vol 358 ◽  
Author(s):  
B.O. Dabbousi ◽  
O. Onitsuka ◽  
M.F. Rubner ◽  
M.G. Bawendi
Keyword(s):  
Thin Films ◽  
Quantum Dots ◽  
Room Temperature ◽  
Variable Temperature ◽  
Cryogenic Temperatures ◽  
Photoluminescence Spectra ◽  
Size Dependent

ABSTRACTWe obtain spectrally narrow (FWHM < 40 nm) electroluminescence from nearly monodisperse CdSe nanocrystallites (quantum dots) incorporated into thin films of polyvinyl carbazole (PVK) and an oxadiazole derivative (PBD) sandwiched between aluminum and ITO electrodes. The electroluminescence and photoluminescence spectra are nearly identical at room temperature and are tunable from ∼530 nm to ∼650 nm by varying the size of the dots. Voltage studies at 77K indicate that while only the dots electroluminesce at the lower voltages, both the dots and the PVK matrix electroluminesce at higher applied voltages. Variable temperature studies indicate that the electroluminescence efficiency increases substantially as the films are cooled down to cryogenic temperatures.

scholarly journals Electron glass signatures up to room temperature in disordered insulators

2022 ◽  
Author(s):  
Julien Delahaye ◽  
Thierry Grenet
Keyword(s):  
Thin Films ◽  
Equilibrium State ◽  
Gate Voltage ◽  
Room Temperature ◽  
Cryogenic Temperatures ◽  
Field Effects ◽  
Non Equilibrium

Abstract This paper describes the observation of non-equilibrium field effects at room temperature in four disordered insulating systems: granular Al, discontinuous Au, amorphous NbSi and amorphous InOx thin films. The use of wide enough gate voltage ranges and a cautious analysis of the data allow us to uncover memory dips, the advocated hallmark of the electron glass, in the four systems. These memory dips are found to relax slowly over days of measurements under gate voltage changes, reflecting the impossibility for the systems to reach an equilibrium state within experimentally accessible times. Our findings demonstrate that these electrical glassy effects, so far essentially reported at cryogenic temperatures, actually extend up to room temperature.

Investigation of Warpage Behavior of Silicon Semiconductor on a Silicon - Adhesive - Ceramic Integrated Structure at Cryogenic Temperatures--STUDENT BEST PAPER $1500

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 001751-001772
Author(s):  
Eyup Can Baloglu ◽  
Tuba Okutucu Ozyurt ◽  
Zafer Dursunkaya
Keyword(s):  
Thermal Cycling ◽  
Silicon Wafer ◽  
Integrated Circuit ◽  
Room Temperature ◽  
Thermal Stresses ◽  
Base Material ◽  
Cryogenic Temperatures ◽  
Readout Integrated Circuit ◽  
Silicon Material ◽  
Integrated Structures

Silicon wafer is widely used as a base material for readout integrated circuit (ROIC) of infrared sensors. There is a heterogeneous component assembly with the silicon wafer material. Warpage behavior of silicon readout integrated circuit is dependent on the material properties and geometrical properties of the integrated materials. Warpage behavior of the silicon material directly affects the warpage of the sensor which must be operated at cryogenic temperatures (around 80 K). There exist a great difference between the operation and storage temperatures (~ 300 K) of these devices. When different materials with different thermal expansion coefficients are used such devices, thermal stresses develop on the components and surface deformations named as “warpage” are observed on the materials. The measurement of excessive thermal stress or warpage formation on the sensor is vital for reliability issues. In this study, warpage behavior of silicon material is examined in the temperature range from room temperature down to cryogenic temperatures (80 K) and under vacuum conditions less than 1 mTorr. The silicon ROIC is integrated on an alumina ceramic by applying an adhesive between these two layers. After the application of the adhesive material, the integration of the silicon to ceramic is accomplished using a pick and place equipment. The warpage of silicon wafer is measured by a Fizeau Laser Interferometer which uses a 633 nanometer wavelength He – Ne laser. The warpage of the diced silicon is measured before and after the integration to the ceramic so that the effect of curing process of the adhesive is determined after which, the warpage of the silicon material is measured at atmospheric pressure and also under vacuum conditions at room temperature. The warpage of silicon material on the integrated structure is measured with increments of 10 K for both cooling from room temperature to 80 K and heating from 80 K to room temperature. In order to reach cryogenic temperatures, a liquid nitrogen cooled vacuum envelope is utilized. The envelope has an optical flat (made of BK7 material and 2.35 mm thick) for interferometric measurements. There are a total of five integrated structures for the warpage measurements. At each of these structures, the silicon material thickness is different. Comparison of the warpage behavior of the silicon material for different thicknesses are performed. Thermal cycling between room temperature and 80 K is also performed up to 5 cycles for each of the integrated structures. Thermal cycling effect on silicon warpage is discussed for silicon - alumina - adhesive trimaterial assembly structure.

Effect of In Situ Doped Nitrogen Concentrations on the Characteristics of Poly 3C-SiC Micro Resonators

2010 ◽  
Vol 645-648 ◽  
pp. 873-876
Author(s):  
Gwiy Sang Chung ◽  
Kyu Hyung Yoon
Keyword(s):  
Thin Films ◽  
Young’S Modulus ◽  
Room Temperature ◽  
Young's Modulus ◽  
Resonant Frequencies ◽  
N Doping ◽  
Nitrogen Concentrations

This paper describes the characteristics of polycrystalline 3C-SiC micro resonators with 3 ×1017 - 1×1019 cm-3 in-situ N-doping concentrations. In this work, the 1.2 μm thick cantilevers and the 0.4 μm thick doubly-clamped beam micro resonators with various lengths were implemented using in-situ doping poly 3C-SiC thin films. The characteristics of the poly 3C-SiC micro resonators were evaluated using quartz actuator and optical read-out vibrometer under vacuum conditions at room temperature. The resonant frequencies of the SiC micro resonators decreased with doping concentrations owing to the reduction of the Young's modulus of the poly 3C-SiC thin films. It was confirmed that the resonant frequencies of the poly 3C-SiC micro- resonators are controllable by adjusting the doping concentrations.

Quartz crystal resonators exhibiting extremely high Q-factors at cryogenic temperatures

2008 ◽  
Vol 44 (14) ◽  
pp. 889 ◽  
Author(s):  
S. Galliou ◽  
J. Imbaud ◽  
R. Bourquin ◽  
N. Bazin ◽  
Ph. Abbé
Keyword(s):  
Quartz Crystal ◽  
Cryogenic Temperatures ◽  
High Q ◽  
Quartz Crystal Resonators ◽  
Q Factors

Cryogenic atomic force microscopy

1991 ◽  
Vol 49 ◽  
pp. 54-55
Author(s):  
K. A. Fisher ◽  
M. G. L. Gustafsson ◽  
M. B. Shattuck ◽  
J. Clarke
Keyword(s):  
Room Temperature ◽  
Rapid Freezing ◽  
Cryogenic Temperatures ◽  
Soft Or ◽  
Electrically Conductive ◽  
Force Microscopy ◽  
Flexible Molecules ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

Investigation of ultra-thin films of YBa2Cu3O7−δ grown on MgO

1990 ◽  
Vol 48 (4) ◽  
pp. 6-7
Author(s):  
S.K. Streiffer ◽  
C.B. Eom ◽  
J.C. Bravman ◽  
T.H. Geballet
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Deposition Process ◽  
Nucleation And Growth ◽  
Multilayer Structures ◽  
Rf Power ◽  
Oxygen Loss ◽  
Transmission Electron ◽  
Single Target ◽  
Mtorr Argon

The study of very thin (<15 nm) YBa2Cu3O7−δ (YBCO) films is necessary both for investigating the nucleation and growth of films of this material and for achieving a better understanding of multilayer structures incorporating such thin YBCO regions. We have used transmission electron microscopy to examine ultra-thin films grown on MgO substrates by single-target, off-axis magnetron sputtering; details of the deposition process have been reported elsewhere. Briefly, polished MgO substrates were attached to a block placed at 90° to the sputtering target and heated to 650 °C. The sputtering was performed in 10 mtorr oxygen and 40 mtorr argon with an rf power of 125 watts. After deposition, the chamber was vented to 500 torr oxygen and allowed to cool to room temperature. Because of YBCO’s susceptibility to environmental degradation and oxygen loss, the technique of Xi, et al. was followed and a protective overlayer of amorphous YBCO was deposited on the just-grown films.

TEM sample preparation of wear-tested room-temperature pulsed-laser-deposited thin films of MoS2 by ultramicrotomy

1993 ◽  
Vol 51 ◽  
pp. 1118-1119
Author(s):  
Pamela F. Lloyd ◽  
Scott D. Walck
Keyword(s):  
Thin Films ◽  
Sample Preparation ◽  
Room Temperature ◽  
High Vacuum ◽  
Pulsed Laser ◽  
Ultra High Vacuum ◽  
Wear Testing ◽  
Preparation Technique ◽  
Cross Sectional ◽  
Aerospace Applications

Pulsed laser deposition (PLD) is a novel technique for the deposition of tribological thin films. MoS2 is the archetypical solid lubricant material for aerospace applications. It provides a low coefficient of friction from cryogenic temperatures to about 350°C and can be used in ultra high vacuum environments. The TEM is ideally suited for studying the microstructural and tribo-chemical changes that occur during wear. The normal cross sectional TEM sample preparation method does not work well because the material’s lubricity causes the sandwich to separate. Walck et al. deposited MoS2 through a mesh mask which gave suitable results for as-deposited films, but the discontinuous nature of the film is unsuitable for wear-testing. To investigate wear-tested, room temperature (RT) PLD MoS2 films, the sample preparation technique of Heuer and Howitt was adapted.Two 300 run thick films were deposited on single crystal NaCl substrates. One was wear-tested on a ball-on-disk tribometer using a 30 gm load at 150 rpm for one minute, and subsequently coated with a heavy layer of evaporated gold.

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