Low Tempeature Lateral Crystallization of Amorphous Silicon on Glass

2002 ◽  
Vol 715 ◽  
Author(s):  
Leila Rezaee ◽  
Aarash Akhavan ◽  
Shamsoddin Mohajerzadeh ◽  
Ali Khakifirooz
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Amorphous Silicon ◽  
Ultra Violet ◽  
Sem Analysis ◽  
Lateral Growth ◽  
Metal Induced Crystallization ◽  
Lateral Growth Rate ◽  
Lateral Crystallization ◽  
Induced Crystallization

AbstractLow temperature lateral growth of amorphous silicon films has been achieved on thin flexible glasses using ultra-violet assisted metal-induced crystallization technique. 125μm ordinary glass substrate is sputter-coated with 1500Å chromium and a 1000Å SiN layer, respectively. 1000Å Si film was deposited using e-beam evaporation at a temperature of 350°C. Equally spaced dots of nickel pads with 140μm separation were used as seed of crystallization of a-Si layer. Crystallinity of the samples was studied using XRD, SEM and optical microscopy. Some crystallographic etchants were used to develop the crystal orientations for SEM analysis. Based on this study, a lateral growth rate of 2μm/hr is obtained at a temperature of 380°C. Activation energy of 1.4 to 1.5eV is extracted for this UV-assisted MILC process.

A Novel Back-Reflecting UV-Assisted Metal-Induced Crystallization of Silicon on Glass

2001 ◽  
Vol 664 ◽  
Author(s):  
Leila Rezaee ◽  
Shamsoddin Mohajerzadeh ◽  
Ali Khakifirooz ◽  
Saber Haji ◽  
Ebrahim Asl Soleimani
Keyword(s):  
Silicon Film ◽  
Crystallization Rate ◽  
Ultra Violet ◽  
Hole Mobility ◽  
Metal Induced Crystallization ◽  
Polysilicon Films ◽  
Novel Method ◽  
Uv Photons ◽  
Lateral Crystallization ◽  
Induced Crystallization

ABSTRACTA novel method of UV-assisted metal-induced-crystallization is introduced to grow polysilicon films on ordinary glass at temperatures as low as 400°C. Annealing is accomplished in the presence of an ultra-violet exposure, leading to high crystallinity of the silicon film as confirmed by XRD, TEM and SEM analyses. A back-reflecting chromium layer is incorporated to further trap UV photons and enhance their absorption in the silicon film. This results in a significant increase in the crystallization rate as studied by XRD spectroscopy. A growth rate of 2 µm/hr is observed at 400 °C, when employing this method for lateral crystallization. Thin-film transistors fabricated using the proposed UV-assisted MILC show a threshold voltage of 1V and hole mobility of about 50 cm2/V.s.

Stress-assisted Copper-induced Lateral Growth of Polycrystalline Germanium

2003 ◽  
Vol 795 ◽  
Author(s):  
B. Hekmatshoar ◽  
D. Shahrjerdi ◽  
S. Mohajerzadeh ◽  
A. Khakifirooz ◽  
M. Robertson ◽  
...  
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Mechanical Stress ◽  
Compressive Stress ◽  
Compressive Strain ◽  
Sem Analysis ◽  
Lateral Growth ◽  
Uniaxial Compressive Stress ◽  
Induced Crystallization ◽  
Pet Substrate

ABSTRACTLateral growth of poly-Ge at temperatures as low as 150°C is reported. External mechanical stress has been properly manipulated to drive the low temperature Cu-induced crystallization of poly-Ge wherever Cu is deposited to form the crystallization seed for lateral growth. Uniaxial compressive stress has been externally applied to the Ge layer by bending the flexible PET substrate inward. A 10-hour period thermo-mechanical post-treatment in the presence of 0.05% equivalent compressive strain leads to a growth rate of 2.5 μm/hour in the direction of the applied stress and 1.8 μm/hour in the perpendicular direction, as confirmed by SEM analysis. We believe that partial growth of the Cu-seeded poly-Ge region in the form of tetragonal structures is the key feature which leads to the lateral growth of the pure-Ge strip. Elimination of the compressive stress hinders the lateral growth completely, even at reasonably high temperatures.

Deposition and Crystallisation Behaviour of Amorphous Silicon Thin Films Obtained by Pyrolysis of Disilane Gas at Very Low Pressure

1994 ◽  
Vol 345 ◽  
Author(s):  
T. Kretz ◽  
D. Pribat ◽  
P. Legagneux ◽  
F. Plais ◽  
O. Huet ◽  
...  
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Electrical Conductance ◽  
Chemical Vapor ◽  
Crystalline Fraction ◽  
Silicon Thin Films ◽  
Crystallisation Behaviour

AbstractHigh purity amorphous silicon layers were obtained by ultrahigh vacuum (millitorr range) chemical vapor deposition (UHVCVD) from disilane gas. The crystalline fraction of the films was monitored by in situ electrical conductance measurements performed during isothermal annealings. The experimental conductance curves were fitted with an analytical expression, from which the characteristic crystallisation time, tc, was extracted. Using the activation energy for the growth rate extracted from our previous work, we were able to determine the activation energy for the nucleation rate for the analysed-films. For the films including small crystallites we have obtained En ∼ 2.8 eV, compared to En ∼ 3.7 eV for the completely amorphous ones.

Power law of molecular weight dependence of lateral growth rate of isotactic polypropylene

Polymer ◽  
2006 ◽  
Vol 47 (21) ◽  
pp. 7601-7606 ◽  
Author(s):  
Koji Yamada ◽  
Kaori Watanabe ◽  
Kiyoka Okada ◽  
Akihiko Toda ◽  
Masamichi Hikosaka
Keyword(s):  
Molecular Weight ◽  
Growth Rate ◽  
Power Law ◽  
Isotactic Polypropylene ◽  
Lateral Growth ◽  
Molecular Weight Dependence ◽  
Lateral Growth Rate

Effects of the lateral growth rate on wood quality parameters of Eucalyptus grandis from different latitudes in Brazil and Argentina

2009 ◽  
Vol 257 (10) ◽  
pp. 2175-2181 ◽  
Author(s):  
Miho Kojima ◽  
Fabio Minoru Yamaji ◽  
Hiroyuki Yamamoto ◽  
Masato Yoshida ◽  
Takahisa Nakai
Keyword(s):  
Growth Rate ◽  
Wood Quality ◽  
Eucalyptus Grandis ◽  
Quality Parameters ◽  
Lateral Growth ◽  
Lateral Growth Rate

Optimization of the metal/silicon ratio on nickel assisted crystallization of amorphous silicon

2005 ◽  
Vol 869 ◽  
Author(s):  
L. Pereira ◽  
M. Beckers ◽  
R.M.S. Martins ◽  
E. Fortunato ◽  
R. Martins
Keyword(s):  
Amorphous Silicon ◽  
Spectroscopic Ellipsometry ◽  
Crystallization Time ◽  
Crystalline Fraction ◽  
Nickel Metal ◽  
Metal Induced Crystallization ◽  
Structural Improvement ◽  
Short Annealing ◽  
The One ◽  
Induced Crystallization

AbstractThe aim of this work is to optimize the metal/silicon ratio on nickel metal induced crystallization of silicon. For this purpose amorphous silicon layers with 80, 125 and 220 nm thick were used on the top of which 0.5 nm of Ni was deposited and annealed during the required time to full crystallize the a-Si. The data show that the 80 nm a-Si layer reaches a crystalline fraction of 95.7% (as detected by spectroscopic ellipsometry) after annealed for only 2 hours. No significant structural improvement is detected by ellipsometry neither by XRD when annealing the films for longer times. However, on 125 nm thick samples, after annealing for 2 hours the crystalline fraction is only 59.7%, reaching a similar value to the one with 80 nm only after 5 hours, with a crystalline fraction of 92.2%. Here again no significant improvements were achieved by using longer annealing times. Finally, the 220 nm thick a-Si sample is completely crystallized only after 10 hours annealing. These data clear suggest that the crystallization of thicker a-Si layers requires thicker Ni films to be effective for short annealing times. A direct dependence of the crystallization time on the metal/silicon ratio was observed and estimated.

A New Field-Aided Germanium-Induced Lateral Crystallization of Silicon

2001 ◽  
Vol 664 ◽  
Author(s):  
Kianoush Naeli ◽  
Shamsoddin Mohajerzadeh ◽  
Ali Khakifirooz ◽  
Saber Haji ◽  
Ebrahim A. Soleimani
Keyword(s):  
Electric Field ◽  
Grain Growth ◽  
Negative Electrode ◽  
Crystallization Rate ◽  
Lateral Growth ◽  
Annealing Temperatures ◽  
Lateral Crystallization ◽  
Si Films ◽  
First Time ◽  
Induced Crystallization

ABSTRACTThe effect of an electric field on germanium-seeded lateral crystallization of a-Si is studied for the first time and compared to this effect in Ni-induced lateral growth. While the crystallization rate is lower when Ge is used as the nucleation seed and annealing should be done at higher temperatures, filed-aided crystallization shows a similar behavior to that observed for Ni-induced crystallization. Optical microscopy results indicate that grain growth starting from the negative electrode occurs in Si films at annealing temperatures higher than 480°C, while the applied electric field ranges form 200 to 1400V/cm. SEM was also used to confirm the crystallinity of the films.

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