Two-Beam Laser Recrystallization of Silicon on an Insulating Substrate

1985 ◽  
Vol 53 ◽  
Author(s):  
Samhita Dasgupta ◽  
Howard E. Jackson ◽  
Joseph T. Boyd
Keyword(s):  
Laser Power ◽  
Silicon On Insulator ◽  
Spatial Control ◽  
Substrate Heating ◽  
Beam Laser ◽  
Laser Recrystallization ◽  
Polysilicon Films ◽  
Power Densities ◽  
Substrate Temperatures

ABSTRACTLaser recrystallization of silicon on an insulating substrate has been carried out by irradiating polysilicon with both an Ar+ laser operating on all lines in the visible and a CO2 laser operating at 10.6 microns. These experiments were carried out over a variety of laser power densities and substrate temperatures. The use of the two lasers allowed for independent spatial control of temperature in both the polysilicon and the SiO2 layers and helped to reduce the strain at the polysilicon - SiO2 interface. We report the successful recrystallization of polysilicon films without substrate heating for two different silicon-on-insulator structures.

Subboundary Free Submicronic Devices on Laser-Recrystallized Silicon Oninsulator

1984 ◽  
Vol 35 ◽  
Author(s):  
A.J. Auberton-Herve ◽  
J.P. Joly ◽  
J.M. Hode ◽  
J.C. Castagna
Keyword(s):  
Channel Length ◽  
Silicon On Insulator ◽  
Ring Oscillator ◽  
Mos Transistors ◽  
Seed Structure ◽  
Leakage Currents ◽  
Industrial Processing ◽  
Laser Recrystallization ◽  
Dynamic Performances ◽  
Lateral Epitaxy

ABSTRACTSeeding from bulk silicon (lateral epitaxy) has been used in Ar+ laser recrystallization to achieve subboundary free silicon on insulator areas. On these areas C.MOS devices have been performed using almost entirely the standard processing steps of a bulk micronic C-MOS technology. n -MOS transistors with channel length as small as 0.3 um have shown very small leakage currents. This is attributed especially to the lack of subboundaries. A 40 % increase in the dynamic performances in comparison with equivalent size C-MOS bulk devices has been obtained (93 ps of delay time per stage for a 101 stages ring oscillator with 0.8 μm of channel length). This is the best result presented so far on recrystallized SOI. No special requirements are needed in the lay out of the circuit with the chosen seed structure. Furthermore an industrial processing rate for the laser recrystallization processing has been achieved using an elliptical laser beam, a high scan velocity (30 cm/s) and a 100 μm line to line scan step (a 4' wafer in 4 minutes).

Deposition of Polysilicon Films by Hot-Wire CVD at Low Temperatures for Photovoltaic Applications

1995 ◽  
Vol 377 ◽  
Author(s):  
J. Puigdollers ◽  
J. Bertomeu ◽  
J. Cifre ◽  
J. Andreu ◽  
J. C. Delgado
Keyword(s):  
Gas Phase ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Amorphous Phases ◽  
Photovoltaic Applications ◽  
Polysilicon Films ◽  
Hydrogen Mixtures ◽  
Si Films ◽  
Substrate Temperatures ◽  
Very High

ABSTRACTPolysilicon (poly-Si) thin films have been obtained using hot-wire chemical vapor deposition (HWCVD) from silane-hydrogen mixtures. The films were prepared at low substrate temperatures (down to 200°C) and at very high deposition rates (up to 40 Å/s). They showed good crystalline properties and no amorphous phases were detected. The films can also be efficiently doped by adding diborane or phosphine to gas phase. In this paper, an overview of the properties of the poly-Si films, intrinsic and p and n-doped, deposited at our laboratory by HWCVD is presented and discussed. The properties of the material and the features of the deposition technique which are interesting for their application in photovoltaics are emphasized.

Reduced Absorption of Light at High Laser Power Densities

Nature ◽  
1965 ◽  
Vol 207 (4995) ◽  
pp. 399-400 ◽  
Author(s):  
HUBERTUS STAERK ◽  
GEORG CZERLINSKI
Keyword(s):  
Laser Power ◽  
High Laser Power ◽  
High Laser ◽  
Absorption Of Light ◽  
Power Densities

Synthesis of Buried Silicon Compounds Using Ion Implantation

1988 ◽  
Vol 100 ◽  
Author(s):  
Alice E. White ◽  
K. T. Short ◽  
R. C. Dynes ◽  
J. M. Gibson ◽  
R. Hull
Keyword(s):  
Ion Implantation ◽  
Surface Damage ◽  
Silicon On Insulator ◽  
High Current ◽  
New Materials ◽  
Compound Formation ◽  
Silicon Compounds ◽  
Mechanisms Of Formation ◽  
New Generation ◽  
Substrate Temperatures

ABSTRACTIon implantation is widely used for doping semiconductors at low concentration, but, with the advent of a new generation of high current implanters, synthesizing new materials rather that simply doping them has become feasible. This technique has been successfully applied to fabricating silicon-on-insulator (SOI) structures with oxygen and nitrogen for several years. Since we are interested in understanding the mechanisms of formation of these layers, we have concentrated on sub-stoichiometric implantation doses of oxygen where it is easier to observe the coalescing layer. In order to determine whether this process of compound formation is more general, our studies were expanded to include implantation of the transition metals. Here, elevated substrate temperatures are necessary to minimize Si surface damage. The resulting disilicide layers are of remarkably high quality: they are single crystals in registry with the silicon wafer and they have better residual resistivities than comparable UHV-reacted silicides.

A New Double Laser Recrystallization Technique to Induce Ultra-Large Poly-Si Grains

2001 ◽  
Vol 685 ◽  
Author(s):  
Minghong Lee ◽  
Seungjae Moon ◽  
Mutsuko Hatano ◽  
Costas P. Grigoropoulos
Keyword(s):  
Grain Growth ◽  
Excimer Laser ◽  
Laser Fluence ◽  
Laser Power ◽  
Laser Flash ◽  
Process Window ◽  
Nanosecond Laser ◽  
Solidification Velocity ◽  
Laser Recrystallization ◽  
Nucleation Sites

AbstractA new double laser recrystallization technique that can produce lateral grains of tens of micrometers is presented. A nanosecond laser (excimer or Nd:YLF laser) and a pulse modulated Ar+ laser are used in the experiment. The effect of different parameters on lateral grain growth is investigated. These parameters include the time delay between the two lasers, the excimer laser fluence, the Ar+ laser power and the pulse duration. This process has wide process window and is insensitive to both the excimer laser fluence and the Ar+ laser power fluctuations. Preheating and melting of the a-Si film with the Ar+ laser before firing the excimer laser is found to be necessary for inducting lateral grain growth. The transient excimer laser irradiation is believed to generate nucleation sites for initiating the subsequent lateral grain growth. The solidification dynamics of the process is probed by high spatial and temporal resolution laser flash photography. A lateral solidification velocity of about 10 m/s is observed.

Crystal-Axis-Rotation of Laser-Recrystallized Silicon on Insulator

1989 ◽  
Vol 164 ◽  
Author(s):  
K. Sugahara ◽  
T. Ippóshi ◽  
Y. Inoue ◽  
T. Nishimura ◽  
Y. Akasaka
Keyword(s):  
Thermal Conductivity ◽  
Laser Power ◽  
Rotation Angle ◽  
Defect Density ◽  
Silicon On Insulator ◽  
Bottom Surface ◽  
Crystal Axis ◽  
Scan Speed ◽  
The Difference ◽  
Axis Rotation

AbstractThe relation between the seed pitch and defect density of the laserrecrystallized SOI film was investigated. It was found that the defect density of the SOI increases as the seed pitch increases. The dependences of the laser scan speed and laser power on rotation angle of the SOI film were experimentally and numerically investigated. The crystal-axisrotation of the SOI film was considered to be due to the difference of the temperature between the top and bottom surface of the SOI film near the liquid-solid interface. A polysilicon heat sink structure with high thermal conductivity was newly proposed and was found to reduce the rotation in a small angle.

Waterborne Pathogen Detection Using Raman Spectroscopy

2008 ◽  
Vol 62 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Ashish Tripathi ◽  
Rabih E. Jabbour ◽  
Patrick J. Treado ◽  
Jason H. Neiss ◽  
Matthew P. Nelson ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Laser Power ◽  
Pathogen Detection ◽  
Species Level ◽  
Gram Positive ◽  
Gram Negative ◽  
Waterborne Pathogen ◽  
Water Matrix ◽  
The Impact ◽  
Power Densities

Raman spectroscopy is being evaluated as a candidate technology for waterborne pathogen detection. We have investigated the impact of key experimental and background interference parameters on the bacterial species level identification performance of Raman detection. These parameters include laser-induced photodamage threshold, composition of water matrix, and organism aging in water. The laser-induced photodamage may be minimized by operating a 532 nm continuous wave laser excitation at laser power densities below 2300 W/cm2 for Gram-positive Bacillus atrophaeus (formerly Bacillus globigii, BG) vegetative cells, 2800 W/cm2 for BG spores, and 3500 W/cm2 for Gram-negative E. coli (EC) organisms. In general, Bacillus spore microorganism preparations may be irradiated with higher laser power densities than the equivalent Bacillus vegetative preparations. In order to evaluate the impact of background interference and organism aging, we selected a biomaterials set comprising Gram-positive (anthrax simulants) organisms, Gram-negative (plague simulant) organisms, and proteins (toxin simulants) and constructed a Raman signature classifier that identifies at the species level. Subsequently, we evaluated the impact of tap water and storage time in water (aging) on the classifier performance when characterizing B. thuringiensis spores, BG spores, and EC cell preparations. In general, the measured Raman signatures of biological organisms exhibited minimal spectral variability with respect to the age of a resting suspension and water matrix composition. The observed signature variability did not substantially degrade discrimination performance at the genus and species levels. In addition, Raman chemical imaging spectroscopy was used to distinguish a mixture of BG spores and EC cells at the single cell level.

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