Excimer-Laser Crystallization of Silicon Films: Numerical Simulation of Lateral Solidification

1996 ◽  
Vol 452 ◽  
Author(s):  
Vikas V. Gupta ◽  
H. Jin Song ◽  
James S. Im
Keyword(s):  
Energy Density ◽  
Incident Energy ◽  
Silicon Film ◽  
High Energy ◽  
Silicon Films ◽  
Two Dimensional ◽  
Laser Crystallization ◽  
Vertical Solidification ◽  
Excimer Laser Crystallization ◽  
Melting And Solidification

AbstractWe have utilized a recently developed transient two-dimensional model for simulating localized beam-induced melting and solidification of thin silicon films on SiO2. Specifically, by tailoring the lateral beam profile, we simulate those situations that are encountered in the artificially-controlled superlateral growth (ACSLG) method, in which various techniques are utilized to irradiate the sample in preselected regions of a silicon film. The spatially and temporally localized character of heating is simulated by introducing a time-dependent two-dimensional heat-source function. The evolution of melt-creation and ensuing solidification is studied as a function of incident energy density and film thickness. The results show two distinct types of behavior as a function of incident energy density: at low energy densities, partial melting and predominantly vertical solidification occur; while at high energy densities, complete melting of the irradiated portion of the film is followed by rapid lateral solidification.

The Effect of Film Thickness and Pulse Duration Variation in Excimer Laser Crystallization of Thin Si Films

1996 ◽  
Vol 452 ◽  
Author(s):  
J. P. Leonard ◽  
M. A. Bessette ◽  
V. V. Gupta ◽  
James S. Im
Keyword(s):  
Energy Density ◽  
Film Thickness ◽  
Partial Melting ◽  
Pulse Duration ◽  
Excimer Laser ◽  
Silicon Film ◽  
Silicon Films ◽  
Laser Crystallization ◽  
Crystal Silicon ◽  
Excimer Laser Crystallization

AbstractRecognizing that the processing window in conventional excimer laser crystallization corresponds mainly to the partial melting regime, and that this can be properly simulated using a one-dimensional model, we investigate numerically the melting and solidification of thin silicon films on SiO2. Here a portion of the silicon film is melted and subsequent vertical solidification is initiated from the lower interface bounding the unmelted region. Upper and lower energy density limits for this regime are calculated for crystal silicon films of thickness 10 to 300 nm, and for pulse duration ranging from 10 to 200 ns. These calculations show that increasing pulse duration requires proportionally more incident energy density to partially melt the film, while decreasing film thickness reduces the range of energy densities over which partial melting can occur. The results are explained in terms of characteristic thermal diffusion distances and the enthalpy change associated with melting. In view of the results we discuss optimization of the conventional excimer laser crystallization and the avoidance of complete melting during the process.

Excimer Laser Crystallization of Nanocrystalline Silicon Thin Films

2015 ◽  
Vol 1120-1121 ◽  
pp. 361-368
Author(s):  
Li Jie Deng ◽  
Wei He ◽  
Zheng Ping Li
Keyword(s):  
Thin Films ◽  
Energy Density ◽  
Excimer Laser ◽  
Silicon Film ◽  
Threshold Energy ◽  
Nanocrystalline Silicon ◽  
Lateral Growth ◽  
Laser Crystallization ◽  
Silicon Thin Films ◽  
Excimer Laser Crystallization

Nanocrystalline silicon (nc-Si) thin film on glass substrate is subjected to excimer laser crystallized by varying the laser energy density in the range of 50~600 mJ/cm2. The effect of excimer laser crystallization on the structure of silicon film is investigated using Raman spectroscopy, X-ray diffraction, atomic force microscopy and scanning electron microscopy. The results show that polycrystalline silicon thin films can be obtained by excimer laser crystallization of nc-Si films. A laser threshold energy density of 200 mJ/cm2 is estimated from the change of crystalline fraction and surface roughness of the treated films. The growth of grain is observed and the crystallization mechanism is discussed based on the super lateral growth model. The nanocrystalline silicon grains in the films act as seeds for lateral growth to large grains.

Location-Controlled Large-Grains in Near-Agglomeration Excimer-Laser Crystallized Silicon Films

2000 ◽  
Vol 621 ◽  
Author(s):  
Paul Ch. van der Wilt ◽  
Ryoichi Ishihara ◽  
Jurgen Bertens
Keyword(s):  
Excimer Laser ◽  
Silicon Film ◽  
Small Diameter ◽  
Amorphous Film ◽  
Silicon Films ◽  
Laser Crystallization ◽  
Single Grain ◽  
Excimer Laser Crystallization ◽  
Vertical Growth Phase ◽  
Small Indentation

ABSTRACTLarge grains in thin silicon films were grown by controlling the location of unmolten islands, which are left after near-complete melting of the film during excimer laser crystallization. As the initially amorphous film was first transformed in small grain polycrystalline silicon, these islands contain seeds for crystal growth. To get a single large grain, either the number of seeds was reduced to one or a single one was selected from the seeds by a ‘grain filter’. Former was achieved by making a small indentation in the isolating layer underlying the silicon film so that seeds remain embedded in the indentation. Latter was achieved by making a small diameter hole in the underlying isolating layer, which was filled with amorphous silicon. The lateral growth is preceded by a vertical growth phase during which a single grain is filtered from the initial set of seeds present at the bottom of the hole. In the experiment described, highest yield was achieved for samples in which the melt-depth to hole- diameter ratio was largest.

Excimer Laser Crystallized Amorphous Silicon Films: Effects of Shot Density and Substrate Temperature

1991 ◽  
Vol 219 ◽  
Author(s):  
R. I. Johnson ◽  
G. B. Anderson ◽  
S. E. Ready ◽  
J. B. Boyce
Keyword(s):  
Energy Density ◽  
Substrate Temperature ◽  
Amorphous Silicon ◽  
Laser Energy ◽  
Silicon Films ◽  
Laser Energy Density ◽  
Laser Crystallization ◽  
Average Grain Size ◽  
Substrate Temperatures

ABSTRACTLaser crystallization of a-Si thin films has been shown to produce materials with enhanced electrical properties and devices that are faster and capable of carrying higher currents. The quality of these polycrystalline films depends on a number of parameters such as laser energy density, shot density, substrate temperature, and the quality of the starting material. We find that the average grain size and transport properties of laser crystallized amorphous silicon films increase substantially with laser energy density, increase only slightly with laser shot density, and are unaffected by substrate temperatures of up to 400°C. The best films are those processed in vacuum but films of fair quality can also be obtained in air and nitrogen atmospheres.

Insight into excimer laser crystallization exploiting ellipsometry: Effect of silicon film precursor

2007 ◽  
Vol 515 (19) ◽  
pp. 7508-7512 ◽  
Author(s):  
Maria Losurdo ◽  
Maria M. Giangregorio ◽  
Alberto Sacchetti ◽  
Pio Capezzuto ◽  
Giovanni Bruno ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Silicon Film ◽  
Laser Crystallization ◽  
Excimer Laser Crystallization ◽  
Insight Into

scholarly journals Tailor-made Functional Polymers for Energy Storage and Environmental Applications

2020 ◽  
Vol 74 (9) ◽  
pp. 667-673
Author(s):  
Ali Coskun
Keyword(s):  
Renewable Energy ◽  
Energy Density ◽  
Electrode Materials ◽  
Value Added ◽  
High Energy ◽  
High Energy Density ◽  
General Strategy ◽  
Two Dimensional ◽  
Environmental Challenges ◽  
Battery Capacity

CO2 emissions into the atmosphere account for the majority of environmental challenges and its global impact in the form of climate change is well-documented. Accordingly, the development of new materials approaches to capture and convert CO2 into value-added products is essential. Whereas the increased availability of renewable energy is curbing our reliance on fossil fuels and decreasing CO2 emissions, the widespread adaptation of renewable energy still requires the development of high energy density batteries i.e., lithium ion batteries (LIBs). To address these energy and environmental challenges, our group has been developing porous organic polymers (POPs) with precise control over their porosity and surface chemistry for CO2 capture, separation and conversion. To realize simultaneous CO2 separation and conversion, we are also developing catalytically active two-dimensional membranes and POPs. In the area of LIBs, we have recognized the potential of supramolecular chemistry as a general strategy for solving the capacity-fading problem associated with high energy density electrode materials such as Li-metal, silicon and sulfur, which offer extremely high battery capacity compared to conventional LIBs. Accordingly, we have demonstrated how molecular-level design of one- and two-dimensional supramolecular polymers can be directly translated into an improved electrochemical performance in high energy density LIBs.

Metallic few-layered VSe2nanosheets: high two-dimensional conductivity for flexible in-plane solid-state supercapacitors

2018 ◽  
Vol 6 (18) ◽  
pp. 8299-8306 ◽  
Author(s):  
Chaolun Wang ◽  
Xing Wu ◽  
Yonghui Ma ◽  
Gang Mu ◽  
Yaoyi Li ◽  
...  
Keyword(s):  
Solid State ◽  
Energy Density ◽  
Mechanical Stability ◽  
High Energy ◽  
High Energy Density ◽  
Two Dimensional

Flexible in-plane solid-state supercapacitor fabricated by CVD-grown metallic VSe2nanosheets presents excellent mechanical stability and high energy density.

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