Doping of GaAs From Silane Decomposition Under Pulsed Laser Irradiation

MRS Proceedings ◽

10.1557/proc-29-367 ◽

1983 ◽

Vol 29 ◽

Author(s):

D. Pribat ◽

D. Dieumegard ◽

B. Dessertenne ◽

J. Chaplart

Keyword(s):

High Pressure ◽

Energy Density ◽

Laser Irradiation ◽

Sheet Resistance ◽

Laser Energy ◽

Pulsed Laser ◽

Compensation Mechanism ◽

Yag Laser ◽

Oxygen Penetration ◽

Pulsed Laser Irradiation

ABSTRACTWe have studied silicon incorporation in GaAs subsequent to Nd-YAG laser irradiation through high pressure silane atmospheres. The process involves SiH4 pyrolysis at contact with a laser-melted GaAs surface, and incorporation of the released Si atoms in the melt. SIMS analyses have allowed us to study silicon incorporation as a function of SiH4 pressure, laser energy density and number of laser shots. The high sheet resistance of the doped layers indicates that the silicon atoms are poorly electrically activated. A compensation mechanism is discussed based on oxygen penetration from native GaAs oxide layers.

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Er-Doping in Silicon by Pulsed Laser Irradiation

MRS Proceedings ◽

10.1557/proc-301-61 ◽

1993 ◽

Vol 301 ◽

Cited By ~ 3

Author(s):

Kenshiro Nakashima

Keyword(s):

Energy Density ◽

Laser Irradiation ◽

Laser Energy ◽

Pulsed Laser ◽

Laser Energy Density ◽

Er Doping ◽

Erbium Ions ◽

State Regime ◽

Er Doped ◽

Pulsed Laser Irradiation

ABSTRACTErbium ions were successfully doped in silicon by pulsed laser irradiation above the threshold laser energy density. Photoluminescence peaks at 1.54, 1.59 and 1.64 µm from Er-optical centers were observed after annealing of Er-doped samples. The intensity of the 1.54 µm Er-emission band increased upon increase in the laser energy density, and then gradually decreased after reaching the maximum, due to the laser sputtering of the silicon substrate. Oxygen atoms, which were unintentionally codoped with Er-ions, were found to be distributed in the same region as in Er-ions, and were suggested to play roles to activate Er-optical centers. The maximum concentration of Er-ions doped in the solid state regime were estimated to be the order of 1018 cm−3 by the Rutherford backscattering measurements.

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Formation of polytype microstructure in pulsed-laser-irradiated sapphire substrates

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138099 ◽

1995 ◽

Vol 53 ◽

pp. 344-345

Author(s):

Siqi Cao ◽

A. J. Pedraza ◽

L. F. Allard ◽

D. H. Lowndes

Keyword(s):

Energy Density ◽

Laser Irradiation ◽

Electroless Deposition ◽

Laser Energy ◽

Pulsed Laser ◽

Surface Modifications ◽

Near Surface ◽

Sapphire Substrates ◽

Hcp Structure ◽

Pulsed Laser Irradiation

Surface modifications of wide-gap materials are produced by pulsed laser irradiation. Under given conditions, these near-surface modifications can promote adhesion enhancement of deposited thin film materials, and activation for electroless deposition. AIN decomposes during laser irradiation leaving a metallic film on the surface. High density dislocations were observed in the surface layer of AIN that was laser melted but not decomposed. The laser melted alumina becomes amorphous at a laser energy density of ~1J/cm2. In sapphire, γ-alumina is formed when the sample is laser irradiated in Ar/4%H2. Here, we report the formation of a new structure in laser-irradiated sapphire.Optically polished c-axis sapphire substrates were laser-irradiated in an Ar/4%H2 atmosphere at 4J/cm2 energy density, using a 308 nm-wavelength laser with a pulse duration of ~40 ns. Sapphire (A12O3) has a space group R 3 c and can be described as an hcp structure having oxygen and aluminum layers alternately stacking along the c-axis.

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Low-Energy, Pulsed-Laser Irradiation of Amorphous Silicon: Melting and Resolidification at Two Fronts

MRS Proceedings ◽

10.1557/proc-35-175 ◽

1984 ◽

Vol 35 ◽

Author(s):

W. Sinke ◽

F.W. Saris

Keyword(s):

Amorphous Silicon ◽

Laser Irradiation ◽

Surface Segregation ◽

Crystalline Silicon ◽

Laser Energy ◽

Pulsed Laser ◽

Surface Region ◽

Low Energy ◽

Double Peak Structure ◽

Pulsed Laser Irradiation

ABSTRACTAfter low-energy pulsed-laser irradiation of Cu-implanted silicon, a double-peak structure is observed in the Cu concentration profile, which results from the occurrence of two melts. From Cu surface segregation we calculate the depth of the surface melt. Cu segregation near the position of the amorphous-crystalline interface gives evidence for a self-propagating melt, moving from the surface region towards the crystalline substrate. Measurements of As-redistribution and of sheet resistance as a function of laser energy density in As-implanted silicon are consistent with the crystallization model which is derived from the effects as observed in Cu-implanted silicon.The results imply a large difference in melting temperature, heat conductivity and heat of melting between amorphous silicon and crystalline silicon.

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Electrical Defect Analysis Following Pulsed Laserirradiation of Unimplanted GaAs

MRS Proceedings ◽

10.1557/proc-13-647 ◽

1982 ◽

Vol 13 ◽

Cited By ~ 1

Author(s):

D. Pribat ◽

S. Delage ◽

D. Dieumegard ◽

M. Croset ◽

P.C. Srivastava ◽

...

Keyword(s):

Energy Density ◽

Laser Irradiation ◽

Laser Energy ◽

Subsurface Layer ◽

Defect Analysis ◽

Current Voltage ◽

Capacitance Voltage ◽

Important Barrier ◽

Induced Defects ◽

Pulsed Laser Irradiation

ABSTRACTCurrent-voltage, capacitance-voltage and defect spectroscopy techniques are used to characterize the electrical properties of GaAs crystals after pulsed laser irradiation with either a Nd-YAG or a Ruby laser. I(V) and C(V) measurements performed in conjunction on Au/GaAs Schottky structures after laser irradiation at low energy density show an important barrier lowering, of the order of 300mV. Carrier compensation up to 6×lO16/cm3 is observed in a subsurface layer whose thickness increases with deposited laser energy density. D.L.T.S. is used to study the tail of laser induced defects behind the heavily compensated layer. Finally the results are compared to those obtained following conventional thermal treatment.

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Formation Of A Metastable Nisi Phase On Si Induced By Pulsed Laser Irradiation

MRS Proceedings ◽

10.1557/proc-91-491 ◽

1987 ◽

Vol 91 ◽

Author(s):

F. Priolo ◽

P. Baeri ◽

M.G. rimaldi ◽

E. Rimini

Keyword(s):

Energy Density ◽

Laser Irradiation ◽

Rutherford Backscattering Spectrometry ◽

Pulsed Laser ◽

Surface Melting ◽

Yield Reduction ◽

Density Range ◽

Appreciable Change ◽

Nisi Phase ◽

Pulsed Laser Irradiation

ABSTRACTThermally grown NiSi layers on <111> Si substrates were irradiated by 35 nsec Nd glass laser pulses in the energy density range 0.3−2.0 J/cm2. Time resolved reflectivity measurements were performed during the irradiation to detect surface melting. The samples were analyzed by 2.0 MeV He+ Rutherford Backscattering Spectrometry in combination with channeling effect. The measured threshold for surface melting was 0.5 J/cm2. Irradiation at energy densities higher than 1.3 J/cm2 changed the silicides layer composition because of the mixing with the underlying silicon. In the intermediate energy density range (0.7−1.1 J/cm ) slight changes in composition were observed, a strong alignement of NiSi molecules along the <111> substrate direction was however observed. The measured Xmin was about 30%. It seems then that an epitaxial NiSi phase can be grown by pulsed laser irradiation with a suitable choice of the incident energy density. Work is in progress to identify this new NiSi phase by TEM. However this ordered phase is a metastable one since after anunealing at 250°C, 30min the channeling yield reduction disappeared without any appreciable change in composition.

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Time Resolved Reflectivity Measurements on Pulsed Laser Irradiated Silicon Immersed in Water

MRS Proceedings ◽

10.1557/proc-100-561 ◽

1988 ◽

Vol 100 ◽

Author(s):

X. D. Wu ◽

D. Dijkkamp ◽

T. Venkatesan

Keyword(s):

Energy Density ◽

Laser Irradiation ◽

Incident Energy ◽

Pulsed Laser ◽

Water Layer ◽

Absorbed Energy ◽

Time Resolved ◽

Starting Point ◽

Melt Duration ◽

Pulsed Laser Irradiation

ABSTRACTTime resolved reflectivity (TRR) measurements were carried out during pulsed laser irradiation of silicon immersed in water. It was found that the TRR in water was similar to that in air though the signal deteriorated after about 100 ns from the starting point of the laser for incident energy densities above 1.4 J/cm2 (unlike what is observed in air). The total melt duration in water was about 2.8 to 1.6 times less than that in air at the same absorbed energy density. It was estimated that 20 % of the absorbed energy was taken away by the water layer. For the same energy coupled into the solid the melt-in/regrowth kinetics was speeded up by the presence of the water layer at the surface by about a factor 2 consistant with the results of Polman et. a15.

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Laser-induced microstructural changes and decomposition of aluminum nitride

Journal of Materials Research ◽

10.1557/jmr.1995.0054 ◽

1995 ◽

Vol 10 (1) ◽

pp. 54-62 ◽

Cited By ~ 31

Author(s):

Siqi Cao ◽

A.J. Pedraza ◽

L.F. Allard

Keyword(s):

Laser Irradiation ◽

Fine Particles ◽

Laser Energy ◽

Pulsed Laser ◽

Solid Substrate ◽

Sharp Change ◽

Microstructural Changes ◽

Transmission Electron ◽

Electroless Copper ◽

Pulsed Laser Irradiation

The microstructural changes induced by pulsed laser irradiation in the surface layer of AlN and the initial stage of electroless copper deposition in laser processe specimens have been investigated using transmission electron microscopy (TEM). It was found that a dislocation microstructure is generated by laser processing at laser energy densities of 1.5 J/cm2 or higher. A very sharp change in the dislocation microstructure was seen at a depth of 0.2 to 0.3 μm from the free surface. The dislocation Burgers vector is 〈100〉 and the slip plane is {001}, in agreement with previous reports. AlN was melted and resolidified homo-epitactically from the solid substrate forming a mosaic microstructure with very fine cells having a misorientation of up to 15°. Patches of metallic aluminum were found at the surface of all the specimens irradiated at a laser energy density of 1.5 J/cm2 or higher. Very fine particles of AlN, 20 to 50 nm in diameter, were randomly distributed inside the patches. Immersion of these specimens in an electroless copper bath showed that the electroless solution preferentially etched away aluminum at the Al-AlN interface. At the same time copper islands were deposited in cavities left by AlN particles as well as at the interface with the underlying substrate. These regions are the seeds for further electroless deposition. The TEM observations of laser-induced microstructural changes reported in this paper help to unravel further the mechanisms of adhesion enhancement and surface activation by pulsed laser irradiation.

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Oxidation and Nitridation by Pulsed Laser Irradiation of Solids Immersed in Liquids

MRS Proceedings ◽

10.1557/proc-75-297 ◽

1986 ◽

Vol 75 ◽

Author(s):

S. Roorda ◽

A. Polman ◽

S. B. Ogale ◽

F. W. Saris

Keyword(s):

Laser Irradiation ◽

Rutherford Backscattering Spectrometry ◽

Laser Energy ◽

Pulsed Laser ◽

Laser Pulses ◽

Processing Parameters ◽

Initial Surface ◽

X Ray Diffraction ◽

Compound Formation ◽

Pulsed Laser Irradiation

AbstractNitridation and oxidation of titanium is achieved by pulsed laser irradiation of Ti immersed in liquid ammonia or water. Rutherford Backscattering Spectrometry shows that large amounts of nitrogen and oxygen can be incorporated in the metal surface to a depth of several 1000 Å. X-ray diffraction shows evidence of compound formation. Scanning Electron Microscopy reveals that initial surface texture is smoothed, and that stress induced cracks and holes may appear. Irradiation of Fe and Si immersed in various liquids shows that modification depends on which combination of solid and liquid is used. Influence of processing parameters such as laser-energy density and number of laser pulses on compound formation has been investigated. The process is viewed as a reactive solute incorporation in the laser melted surface layer, followed by compound formation.

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Nanoparticles and Films Formed by Pulsed Laser Irradiation on the CeO2 Target in the Liquid

Materials Science Forum ◽

10.4028/www.scientific.net/msf.475-479.3843 ◽

2005 ◽

Vol 475-479 ◽

pp. 3843-3846

Author(s):

Jiwei Chen ◽

Jing Yang ◽

Jian She Lian

Keyword(s):

Energy Density ◽

Laser Irradiation ◽

Power Density ◽

Pulsed Laser ◽

Ceo2 Nanoparticles ◽

Formation Mechanisms ◽

Nanocrystalline Films ◽

Amorphous Films ◽

Pulsed Laser Irradiation

The irradiation of a Nd-YAG pulsed laser on the CeO2 target in water was investigated. The CeO2 nanoparticles sized of 20-80 nm were formed in water, while the power density was larger than 32 kJ/cm2. The nanocrystalline films with grain sized of 50-150 nm were formed on the target with the energy density of 20 kJ/cm2-25 kJ/cm2. Finally, the amorphous films were formed with the energy density of 6 kJ/cm2-15 kJ/cm2. The formation mechanisms of the nanoparticles and the films were discussed.

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