Surface Modification of Aluminum Nitride and of Aluminum by Excimer Laser

1992 ◽  
Vol 285 ◽  
Author(s):  
A.J. Pedraza ◽  
J.-Y. Zhang ◽  
H. Esrom
Keyword(s):  
Aluminum Nitride ◽  
Excimer Laser ◽  
Substrate Surface ◽  
Ablation Rate ◽  
Laser Wavelength ◽  
Mechanism Of Decomposition ◽  
Self Consistent ◽  
A New Technique ◽  
193 Nm ◽  
Evaporation Kinetics

ABSTRACTA new technique for selective metallization of aluminum nitride (AIN) has been previously reported (1). It involves the use of an excimer laser to activate the AIN surface followed by electroless plating (Cu,Ni,Au) of the irradiated areas. The mechanism of decomposition of ALN is accompanied by ablation and the formation of an Al film on the substrate surface. Ablation rates are reported here as a function of fluence and number of pulses for three different wavelengths λ = 193 nm (ArF), λ = 248 (KrF) and λ = 351 nm (XeF).The effect of laser wavelength on the ablation rate is discussed. The ablation rates for Al were zlso measured and are compared with the AIN ablation rates. A numerical thermal model is used to analyze the mechanisms of laser ablation of both materials. The evaporation kinetics are incorporated into the model. The Clausius-Clapeyron approximation is used to make a self-consistent calculation of boiling and decomposition temperatures.

Excimer laser ablation of aluminum nitride

1997 ◽  
Vol 12 (1) ◽  
pp. 218-225 ◽  
Author(s):  
Janet K. Lumpp ◽  
Susan D. Allen
Keyword(s):  
Aluminum Nitride ◽  
Excimer Laser ◽  
Ablation Threshold ◽  
Statistical Design ◽  
Ablation Rate ◽  
Data Sets ◽  
Statistical Design Of Experiments ◽  
Excimer Laser Ablation ◽  
High Fluences ◽  
Processing Variables

Excimer laser wavelengths ablate aluminum nitride at rates up to 0.2 μm/pulse where the rate increases with decreasing background pressure and increasing fluence. The ablation threshold for AlN at 248 nm is approximately 2 J/cm2. Blind vias are produced with flat bottoms, straight walls, and a decomposed metallic layer remaining on the surface. Ablation rate dependence on fluence saturates at high fluences due to absorption by the ablation plume. The influence of processing variables on ablation rate and ablation mechanisms are discussed. Statistical design of experiments is used to compare data sets.

Modeling of Silicon Deposition Yield at Low Temperature by ArF Excimer Laser Photolysis of Disilane

1992 ◽  
Vol 263 ◽  
Author(s):  
B. Fowler ◽  
S. Lian ◽  
S. Krishnan ◽  
C. Li ◽  
L. Jung ◽  
...  
Keyword(s):  
Gas Phase ◽  
Excimer Laser ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Film Deposition ◽  
Growth Surface ◽  
Phase Reaction ◽  
Gas Phase Reactions ◽  
Arf Excimer Laser ◽  
193 Nm

ABSTRACTNon-thermal Chemical Vapor Deposition (CVD) such as laser-enhanced photo-CVD of Si at low temperatures is important for Si-based heterostructures and doping superlattices. Growth kinetic models must be developed to allow these processes to be fully exploited. Intrinsic Si epitaxial layers were deposited at low substrate temperatures of 250-350ºC using the 193 nm output of an ArF excimer laser to directly dissociate Si2H6. The intrinsic film deposition rate can be described by a kinetic model that considers the gas phase reactions of the primary photolysis products and diffusion ofsilicon-bearing molecules to the growth surface. With the laser beam tangential to the substrate surface, growth rates as a function of beam-to-substrate distance have been characterized and indicate that very little gas phase reaction occurs for the dominant Si growth precursor. In order for intrinsic film deposition to result solely from Si2H6 photolysis products, a sticking coefficient ≥ 0.6 must be assigned to the dominant growth precursor in order to fit the observed yield of Si deposited in the films, indicating that the dominant growth precursor in 193 nm Si2H6 photolysis is perhaps H2SiSiH2.

Fluence Dependence of Excimer Laser Ablation of Ain

1993 ◽  
Vol 323 ◽  
Author(s):  
Janet K. Lumpp ◽  
Christopher N. Coretsopoulos ◽  
Susan D. Allen
Keyword(s):  
Shock Waves ◽  
Aluminum Nitride ◽  
Excimer Laser ◽  
Rapid Heating ◽  
Emission Spectra ◽  
Sample Surface ◽  
Ablation Rate ◽  
Beam Deflection ◽  
Metallic Surface ◽  
Surface Emission

AbstractAluminum nitride has been ablated with a KrF excimer laser (248 nm) at fluences from 1 to 60 J/cm2. Ablation depth, emission spectra and photothermal beam deflection were detected as a function of fluence. An ablation rate of 0.2 μm/pulse was achieved above 30 J/cm2 in vacuum. Ablation rate decreased with decreasing, fluence. Irradiated surfaces have a conductive metallic layer of reduced aluminum nitride. At low fluences, the metallic surface layer was spotty within the area of the laser beam. Below the fluence threshold for producing the metallized surface, emission spectra and photothermal beam deflection were still detected. Emission lines from Al, Al+ and Al-N were observed. Photothermal deflection data was used to calculate supersonic velocities for shock waves propagating from the sample surface. Shock waves resulted from rapid heating near the surface and expansion of ablated material from the laser spot.

Excimer Laser Induced Photolytic Deposition of Aluminum Nitride: Ftlm Growth and Properties

1995 ◽  
Vol 397 ◽  
Author(s):  
G. Radhakrishnan ◽  
P.M. Adams ◽  
N. Marquez
Keyword(s):  
Electron Microscopy ◽  
Aluminum Nitride ◽  
Substrate Temperature ◽  
Gas Phase ◽  
Excimer Laser ◽  
Film Growth ◽  
Aln Film ◽  
Fused Quartz ◽  
Photolysis Laser ◽  
193 Nm

ABSTRACTExcimer laser photolysis has been used for the growth of smooth and well-adhering thin films of aluminum nitride (AlN) on Si, fused quartz, and KBr substrates at temperatures as low as 350 K. The photolysis was carried out at 193 nm, with the laser beam propagating parallel to the substrate. Trimethylamine alane and ammonia were used as gas-phase precursors. The growth rate of these films was investigated as a function of laser fluence. These measurements, as well as other investigations of film growth with and without the photolysis laser, reveal that no AlN film is produced in the absence of laser-induced photolysis of the precursors. The morphology and physical properties of these laser-grown films have been studied by scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. Optical absorption spectra of films grown on fused quartz were measured as a function of substrate temperature. A substrate temperature of 350 K was found to be optimum for obtaining good film quality while precluding any effects due to the thermal decomposition of the precursors. The films have excellent dielectric properties as shown by I-V and C-V measurements. The details of AlN film growth using low-temperature gas-phase photolysis at 193 nm and the characterization of these laser grown films will be discussed.

Ablation Rate of Human Corneal Epithelium and Bowman's Layer With the Excimer Laser (193 nm)

1990 ◽  
Vol 6 (2) ◽  
pp. 99-99
Author(s):  
Theo Seiler ◽  
Martin Kriegerowski ◽  
Norbert Schnoy ◽  
Thomas Bende
Keyword(s):  
Excimer Laser ◽  
Corneal Epithelium ◽  
Ablation Rate ◽  
Human Corneal Epithelium ◽  
193 Nm

Characterization of Excimer Laser Deposited Gaas Films From the Photolysis of Trimethylgallium and Trimethylarsine At 193 nm

1986 ◽  
Vol 75 ◽  
Author(s):  
V. R. Mccrary ◽  
V. M. Donnelly ◽  
D. Brasen ◽  
A. Appelbaum ◽  
R. C. Farrow
Keyword(s):  
Electron Microscopy ◽  
Excimer Laser ◽  
Deposition Process ◽  
Laser Wavelength ◽  
Time Resolved ◽  
Laser Fluences ◽  
Transmission Electron ◽  
Gaas Films ◽  
193 Nm

AbstractThe growth of GaAs thin films from the excimer laser photolysis of trimethylarsine (TMAs) and trimethylgallium (TMGa) at 193 nm is reported. Scanning electron microscopy (SEM), electron channeling, Rutherford backscattering spectroscopy (RBS), transmission electron microscopy (TEM), and Auger electron spectroscopy (AES) were used to characterize the films. Incident laser fluences on the surface of 0.096–0.115 J/cm2 lead to carbon desorption, adatom mobility, transient annealing and hence epitaxial growth. However, TEM micrographs also revealed the growth of GaAs twins along the <110> direction in a novel periodic fashion, with a spacing equal to that of the ArF excimer laser wavelength (193 nm). Time-resolved mass spectrometry, used to determine gas-phase photolysis products created during the deposition process, showed that AsCH3 and higher gallium-alkyls are significant products which transport As and Ga to the surface.

scholarly journals Stress Transients Generated by Excimer-Laser Irradiation of Polyimide

1992 ◽  
Vol 285 ◽  
Author(s):  
A. D. Zweig ◽  
V. Venugopalan ◽  
T. F. Deutsch
Keyword(s):  
Thermal Decomposition ◽  
Laser Irradiation ◽  
Excimer Laser ◽  
Polyvinylidene Fluoride ◽  
Laser Wavelength ◽  
Stress Generation ◽  
Physical Mechanisms ◽  
Gas Dynamic ◽  
Excimer Laser Irradiation ◽  
193 Nm

ABSTRACTWe measure the stress transients resulting from pulsed excimer laser irradiation of polyimide at 351, 308, 248 and 193 nm, using thin (9 μm) piezoelectric PVDF (polyvinylidene fluoride) films. We find that fluences between 3·10−3 and 102 J/cm2 generate peak stresses between 104 and 109 Pa. Further, the results show three ranges of fluence where different physical mechanisms mediate the stress generation. In the lowest range of fluence, subsurface thermal decomposition (for λ = 351 and 308 nm) and photodecomposition (for λ = 248 and 193 nm) govern the generation of the observed stresses. At higher fluences we identify two regimes, independent of laser wavelength, where the gas dynamic expansion of the ablation products and plasma formation and expansion, are responsible for the generated stresses.

scholarly journals Preparation and Properties of Superconducting thin Films by Excimer Laser Ablation

1990 ◽  
Vol 191 ◽  
Author(s):  
Michael E. Geusic ◽  
Alan F. Stewart ◽  
Larry R. Pederson ◽  
William J. Weber ◽  
Kenneth R. Marken ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Excimer Laser ◽  
Laser Energy ◽  
Substrate Surface ◽  
Xrd Analysis ◽  
Zero Field ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Excimer Laser Ablation

ABSTRACTExcimer laser ablation with an in situ heat treatment was used to prepare high quality superconducting YBa2Cu3O7−x thin films on (100)-SrTiO3 and (100)-LaAlO3 substrates. A pulsed excimer laser (XeCl; 308 nm) was used to ablate a rotating, bulk YBa2Cu3O7−x target at a laser energy density of 2–3 J/cm2. Based on four-probe dc resistance measurements, the films exhibited superconducting transition temperatures (Tc, midpoint) of 88 and 87K with 2K (90–10%) transition widths for SrTiO3 and LaAlO3, respectively. Transport critical current densities (Jc) measured at 77K were 2 × 106 and 1 × 106 A/cm2 in zero field for SrTiO3 and LaAlO3, respectively. X-ray diffraction (XRD) analysis showed the films to be highly oriented, with the c-axis perpendicular to the substrate surface.

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