scholarly journals Photothermal Effects and Heat Conduction in Nanogranular Silicon Films

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2379
Author(s):  
Bayan A. Kurbanova ◽  
Gauhar K. Mussabek ◽  
Viktor Y. Timoshenko ◽  
Vladimir Lysenko ◽  
Zhandos N. Utegulov
Keyword(s):  
Phonon Scattering ◽  
Hexagonal Phase ◽  
Interface Bonding ◽  
Fem Modeling ◽  
Element Mesh ◽  
Glass Substrates ◽  
Si Nanoparticles ◽  
Si Films ◽  
Conductive Properties ◽  
Difference Time

We present results on the photothermal (PT) and heat conductive properties of nanogranular silicon (Si) films synthesized by evaporation of colloidal droplets (drop-casting) of 100 ± 50 nm-sized crystalline Si nanoparticles (NP) deposited on glass substrates. Simulations of the absorbed light intensity and photo-induced temperature distribution across the Si NP films were carried out by using the Finite difference time domain (FDTD) and finite element mesh (FEM) modeling and the obtained data were compared with the local temperatures measured by micro-Raman spectroscopy and then was used for determining the heat conductivities k in the films of various thicknesses. The cubic-to-hexagonal phase transition in Si NP films caused by laser-induced heating was found to be heavily influenced by the film thickness and heat-conductive properties of glass substrate, on which the films were deposited. The k values in drop-casted Si nanogranular films were found to be in the range of lowest k of other types of nanostructurely voided Si films due to enhanced phonon scattering across inherently voided topology, weak NP-NP and NP-substrate interface bonding within nanogranular Si films.

scholarly journals Photothermal Effects and Heat Conduction in Nanogranular Silicon Films

2021 ◽  
Author(s):  
Bayan A. Kurbanova ◽  
Gauhar K Mussabek ◽  
Viktor Y. Timoshenko ◽  
Vladimir Lysenko ◽  
Zhandos N. Utegulov
Keyword(s):  
Phonon Scattering ◽  
Hexagonal Phase ◽  
Fem Modeling ◽  
Element Mesh ◽  
Glass Substrates ◽  
Si Nanoparticles ◽  
Si Films ◽  
Conductive Properties ◽  
Difference Time

We present the results on photothermal (PT) and heat conductive properties of nanogranular silicon (Si) films synthesized by evaporation of colloidal droplets (drop-casting) of 100 ± 50 nm sized crystalline Si nanoparticles (NP) deposited on glass substrates. Finite difference time domain (FDTD) and finite element mesh (FEM) modeling of absorbed light intensity and photo-induced spatial temperature distribution across the Si NP films were well correlated with the local temperatures measured by micro-Raman spectroscopy and used for determination of heat conductivities in the films of various thicknesses. Cubic-to-hexagonal phase transition in these films caused by laser heating was found to be heavily influenced by the film thickness and heat conductive properties of glass substrate, on which the films were deposited. Heat conductivities across the drop-casted Si nanogranular films were found to be in the range of lowest heat conductivities of other types of nanostructurely voided Si films due to enhanced phonon scattering across inherently voided topology, weak NP-NP and NP-substrate interface bonding within nanogranular Si films.

Rapid Epitaxial Growth of Si and SiGe Mono-Crystalline Films on Silicon-on-Glass Substrates by Reactive CVD Using SiH4, GeH4, and F2

2012 ◽  
Vol 1426 ◽  
pp. 331-337
Author(s):  
Hiroshi Noge ◽  
Akira Okada ◽  
Ta-Ko Chuang ◽  
J. Greg Couillard ◽  
Michio Kondo
Keyword(s):  
Epitaxial Growth ◽  
Heating Temperature ◽  
Exothermic Reaction ◽  
Epitaxial Films ◽  
Si Substrates ◽  
Glass Substrates ◽  
Good Crystallinity ◽  
Crystalline Films ◽  
Si Films ◽  
First Time

ABSTRACTWe have succeeded in the rapid epitaxial growth of Si, Ge, and SiGe films on Si substrates below 670 ºC by reactive CVD utilizing the spontaneous exothermic reaction between SiH4, GeH4, and F2. Mono-crystalline SiGe epitaxial films with Ge composition ranging from 0.1 to 1.0 have been successfully grown by reactive CVD for the first time.This technique has also been successfully applied to the growth of these films on silicon-on-glass substrates by a 20 - 50 ºC increase of the heating temperature. Over 10 μm thick epitaxial films at 3 nm/s growth rate are obtained. The etch pit density of the 5.2 μm-thick Si0.5Ge0.5 film is as low as 5 x 106 cm-2 on top. Mobilities of the undoped SiGe and Si films are 180 to 550 cm2/Vs, confirming the good crystallinity of the epitaxial films.

Optical, Structural and Electrical Characteristics of Explosively Crystallized Si Thin Films on Glass Substrates

1981 ◽  
Vol 4 ◽  
Author(s):  
G. Auvert ◽  
D. Bensahel ◽  
A. Perio ◽  
F. Morin ◽  
G.A. Rozgonyi ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Laser Annealing ◽  
The State ◽  
Electrical Characteristics ◽  
Glass Substrates ◽  
Explosive Crystallization ◽  
Cw Laser ◽  
Structural And Electrical Properties ◽  
Si Films

ABSTRACTExplosive Crystallization occurs in cw laser annealing on a-Si films deposited on glass substrates at laser scan speeds higher than 30 cm/sec. Optical, structural and electrical properties of the crystallized films at various laser scan speeds confirm the existence of two kinds of explosive growth depending on the state of crystallinity of the starting material.

Stress Reduction of Amorphous Silicon Deposited by PECVD

2016 ◽  
Vol 1812 ◽  
pp. 109-116
Author(s):  
César B. Pérez ◽  
C. Reyes-Betanzo
Keyword(s):  
Residual Stress ◽  
Amorphous Silicon ◽  
Thermal Annealing ◽  
Stress Reduction ◽  
Microfluidic Devices ◽  
Wet Etching ◽  
Glass Substrates ◽  
Deposition Power ◽  
Si Films ◽  
Deposition Conditions

ABSTRACTAmorphous silicon (α-Si) was deposited on glass substrates by PECVD at different deposition conditions in order to characterize the residual stress on the film. Subsequently, a thermal-annealing was applied for different times at 400 °C in a N2 atmosphere, aiming to reduce the stress in the films. The deposition power was between 15 and 30 W at 13.56 MHz, the pressure in the chamber was adjusted in a range from 600 to 900 mTorr, and the temperature was varied from 140 to 200 °C. The stress was determined by using the Stoney equation, measuring the curvature and thickness of the α-Si films with a stylus profilometer. A deposition rate between 7-24 nm/min was obtained, and the time for thermal-annealing needed to reduce the stress was reduced from 10 to 2-4 h, obtaining a minimum compressive stress of 17 MPa. With this value of stress, it was possible to use the α-Si as masking material for wet etching of glass during the manufacturing of microfluidic devices, in order to obtain microstructures in the glass with 150 μm in depth.

scholarly journals Characterization of Defects and Stress in Polycrystalline Silicon Thin Films on Glass Substrates by Raman Microscopy

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Kuninori Kitahara ◽  
Toshitomo Ishii ◽  
Junki Suzuki ◽  
Takuro Bessyo ◽  
Naoki Watanabe
Keyword(s):  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
Solid Phase ◽  
Raman Microscopy ◽  
Laser Crystallization ◽  
Local Vibration ◽  
Optical Phonon Mode ◽  
Glass Substrates ◽  
Silicon Thin Films ◽  
Si Films

Raman microscopy was applied to characterize polycrystalline silicon (poly-Si) on glass substrates for application as thin-film transistors (TFTs) integrated on electronic display panels. This study examines the crystallographic defects and stress in poly-Si films grown by industrial techniques: solid phase crystallization and excimer laser crystallization (ELC). To distinguish the effects of defects and stress on the optical-phonon mode of the Si–Si bond, a semiempirical analysis was performed. The analysis was compared with defect images obtained through electron microscopy and atomic force microscopy. It was found that the Raman intensity for the ELC film is remarkably enhanced by the hillocks and ridges located around grain boundaries, which indicates that Raman spectra mainly reflect the situation around grain boundaries. A combination of the hydrogenation of films and the observation of the Si-hydrogen local-vibration mode is useful to support the analysis on the defects. Raman microscopy is also effective for detecting the plasma-induced damage suffered during device processing and characterizing the performance of Si layer in TFTs.

Mechanism and control of crack generation in glass substrates during crystallization of a-Si Films by flash lamp annealing

2012 ◽  
Vol 358 (17) ◽  
pp. 2154-2158 ◽  
Author(s):  
Keisuke Ohdaira ◽  
Naohito Tomura ◽  
Shohei Ishii ◽  
Keisuke Sawada ◽  
Hideki Matsumura
Keyword(s):  
Flash Lamp ◽  
Glass Substrates ◽  
Crack Generation ◽  
Si Films ◽  
And Control

UV-Optics for Excimer Laser based Crystallization Processes

2001 ◽  
Vol 685 ◽  
Author(s):  
H.-J. Kahlert ◽  
Frank Simon ◽  
Berthold Burghardt
Keyword(s):  
Excimer Laser ◽  
Average Power ◽  
Industrial Applications ◽  
Flat Panel Display ◽  
Uniform Illumination ◽  
Optical Efficiency ◽  
Glass Substrates ◽  
Line Beam ◽  
Si Films ◽  
Polycrystalline Silicon Films

AbstractLaser based crystallization of thin amorphous films on glass substrates have entered into industrial applications since several years. The excimer laser based process provides a low temperature procedure to obtain polycrystalline silicon films on flat panel display substrates to fabricate thin film transistors (TFT's).The key to this application is a uniform illumination of the. Line Beam systems provide up to 365mm long homogeneous exposure fields operated with up to 300 W average power 308nm excimer lasers. The paper covers a technical overview of Line Beam Optics layout, recent developments and results.Further high resolution optics are described and discussed for sequential lateral solidification (SLS) (1,2,3) processes. The SLS application has demonstrated to efficiently produce directionally solidified microstructures or even grain-boundary –free regions on Si-films. Diffraction limited resolution in the range of several micrometers and high optical throughput are important parameters to this application.General considerations are presented to describe technical limits which compromise laser beam related coherence effects, optimum uniform illumination, adequate resolution and depth of focus and optical efficiency for the practical application.

Poly-Silicon Deposition by Evaporation for TFTs

1987 ◽  
Vol 106 ◽  
Author(s):  
W. Schmolla ◽  
J. Diefenbach ◽  
G. Blang ◽  
W. Senske
Keyword(s):  
Ion Implantation ◽  
Borosilicate Glass ◽  
Hall Mobility ◽  
Field Effect ◽  
Current Ratio ◽  
Glass Substrates ◽  
Threshold Voltages ◽  
Electron Field ◽  
Evaporation Technique ◽  
Si Films

ABSTRACTPoly-Si films were e-gun evaporated onto glass substrates. The Hall-mobility for holes was found to be about 2 cm2/Vs in undoped poly-Si films deposited at 400°C and 9 cm2/Vs at 500°C. TFTs were fabricated on the base of poly-Si evaporation technique on borosilicate glass at a highest process temperature of 550°C without ion implantation. The electrical TFT characteristics yield electron field-effect mobilities higher than 10 cm2/Vs as well as threshold voltages less than IV and an on/off current ratio in excess of 104.

Characterization of Grain Boundary Geometry in the TEM, Exemplified in Si Thin Films

2012 ◽  
Vol 186 ◽  
pp. 7-12 ◽  
Author(s):  
János L. Lábár ◽  
Ákos K. Kiss ◽  
Silke Christiansen ◽  
Fritz Falk
Keyword(s):  
Thin Films ◽  
Degrees Of Freedom ◽  
Sample Surface ◽  
High Energy ◽  
High Energy Density ◽  
Glass Substrates ◽  
Low Dimensional ◽  
Si Films ◽  
Alternative Routes

A method is presented here for complete geometrical characterization of grain boundaries, based on measurement of thin films in the TEM. First, the three parameters, characterizing the misorientation of the two neighboring grains are determined from convergent beam electron diffraction (CBED). Next, the last two (of the total five macroscopic degrees of freedom) parameters are determined from bright field (BF) images to describe the orientation of the boundary plane between them. Ambiguity in the tilt direction of the plane is resolved from BF images recorded at two distinct goniometer settings. Application of the method is demonstrated in Silicon thin films. GB-plane distribution in a thin film is not necessarily identical to the distribution of similar planes in bulk materials. It was observed in low dimensional fcc metals (wires or thin films) that energy minimization of GBs can follow two (mainly alternative) routes. Either low energy planes (like {111}) are formed in 3 boundaries, or alternatively, it is observed that the GB plane has a general index (and high energy density) but it ends at both free surfaces of the sample, resulting in a GB, almost normal to the sample surface, minimizing the total area of the GB. We observed that this later type of planes is mainly characteristic of non-3 boundaries in thin Si films, crystallized from melt on glass substrates (separated by a thin SiN barrier layer). This observation is important for the expected recombination properties of the multicrystalline Si (m-Si) in planned solar cell (SC) applications.

Low Temperature Polycrystalline Si TFTs Fabricated with Directionally Crystallized Si Film

2000 ◽  
Vol 621 ◽  
Author(s):  
Y.H. Jung ◽  
J.M. Yoon ◽  
M.S. Yang ◽  
W.K. Park ◽  
H.S. Soh ◽  
...  
Keyword(s):  
Low Temperature ◽  
Current Flow ◽  
Drain Current ◽  
Directionally Solidified ◽  
Channel Mobility ◽  
Glass Substrates ◽  
Average Grain Size ◽  
Sequential Lateral Solidification ◽  
Si Films ◽  
Channel Region

ABSTRACTThe comparison of TFTs fabricated on films processed by conventional excimer laser an- nealing (ELA) and sequential lateral solidification (SLS) demonstrates the dependence of the device characteristics on the microstructure of the device channel region. We report the perform- ance characteristics of non-self-aligned coplanar n- and p-channel low temperature TFTs fabricated on 1000-Å-thick films on Corning 1737 glass substrates that were directionally solidified using SLS. The devices were aligned so that the grain boundaries were parallel to the direction of the source-drain current flow. These results were compared with those obtained from devices fabricated on conventional ELA-processed polycrystalline Si films (with average grain size of ∼3000 Å) with identical methods. The values for channel mobility obtained from the SLS TFTs are ∼370 cm2/Vsec for n-channel and ∼140 cm2/Vsec for p-channel devices, compared to ∼100 and ∼60 respectively for ELA TFTs. Other device characteristics of SLS TFTs were Ion/Ioff > 107 at Vd=0.1V, and subthreshold slopes less than 0.5V/dec. We further discuss the physical implications of the results and present additional details of the devices.

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