Microstructural changes of Aluminum Nitride after laser irradiation and electroless copper deposition

1994 ◽  
Vol 52 ◽  
pp. 636-637
Author(s):  
S. Cao ◽  
A. J. Pedraza ◽  
L. F. Allard
Keyword(s):  
Aluminum Nitride ◽  
Laser Irradiation ◽  
Electroless Deposition ◽  
Thermal Evaporation ◽  
Surface Region ◽  
Near Surface ◽  
Laser Patterning ◽  
Electroless Copper ◽  
Excimer Laser Irradiation ◽  
Laser Effect

Excimer-laser irradiation strongly modifies the near-surface region of aluminum nitride (AIN) substrates. The surface acquires a distinctive metallic appearance and the electrical resistivity of the near-surface region drastically decreases after laser irradiation. These results indicate that Al forms at the surface as a result of the decomposition of the Al (which has been confirmed by XPS). A computer model that incorporates two opposing phenomena, decomposition of the AIN that leaves a metallic Al film on the surface, and thermal evaporation of the Al, demonstrated that saturation of film thickness and, hence, of electrical resistance is reached when the rate of Al evaporation equals the rate of AIN decomposition. In an electroless copper bath, Cu is only deposited in laser-irradiated areas. This laser effect has been designated laser activation for electroless deposition. Laser activation eliminates the need of seeding for nucleating the initial layer of electroless Cu. Thus, AIN metallization can be achieved by laser patterning followed by electroless deposition.

Electroless copper films deposited onto laser-activated aluminum nitride and alumina

1994 ◽  
Vol 9 (4) ◽  
pp. 1019-1027 ◽  
Author(s):  
M. J. DeSilva ◽  
A. J. Pedraza ◽  
D.H. Lowndes
Keyword(s):  
Energy Density ◽  
Aluminum Nitride ◽  
Laser Irradiation ◽  
Laser Energy ◽  
Annealing Treatment ◽  
Surface Region ◽  
Laser Energy Density ◽  
Copper Films ◽  
Near Surface ◽  
Electroless Copper

Metallization of ceramic substrates by laser activation and subsequent electroless deposition has been demonstrated recently in aluminum nitride and alumina. However, the bond strength between the electroless copper and the ceiamic substrate is weak (less than 14 MPa). Low temperature annealing of electroless copper films deposited on substrates activated at low laser energies strongly increases the adhesion strength. The effectiveness of the annealing for improving the metal-ceramic bonding is dependent upon the laser treatment performed on the substrate prior to deposition. Faster deposition kinetics are obtained for both substrates by increasing the laser energy density. On the other hand, an increase in the laser energy density leads to poor adhesion strengths. The dislocation microstructure produced during laser irradiation in aluminum nitride is analyzed as a possible cause of laser activation. Free aluminum produced by laser irradiation of aluminum nitride and of alumina is discussed as another factor of laser activation. The chemical and microstructural changes taking place in the near-surface region as a consequence of laser-induced processes are correlated with adhesion enhancement promoted by the annealing treatment.

Excimer Laser Irradiation of Metallic Films on Ceramic Substrates

1991 ◽  
Vol 235 ◽  
Author(s):  
M. J. Godbole ◽  
A. J. Pedraza ◽  
D. H. Lowndes ◽  
J. R. Thompson
Keyword(s):  
Energy Density ◽  
Laser Irradiation ◽  
Surface Region ◽  
Copper Films ◽  
Metallic Films ◽  
Ceramic Substrates ◽  
Near Surface ◽  
Excimer Laser Irradiation ◽  
Sputter Deposited ◽  
Density Threshold

ABSTRACTCopper films sputter deposited on mechanically polished (optical finish) and on annealed substrates were laser-irradiated at various energy densities. The effect of the substrate condition on both the evaporation threshold and the morphology of the laser-irradiated metallic films was investigated. The energy density threshold for laser-induced evaporation of the copper films was studied using energy dispersive x-ray spectroscopy (EDS) in a scanning electron microscope (SEM). It was found that for annealed substrates the energy density threshold decreases relative to the threshold for the as-polished condition. These results are compared with predictions of a mathematical model that assumes that the near surface region of the as-polished ceramic is a highly damaged region and, thus, constitutes a thermal barrier. The film remains intact and with almost no change in morphology after laser irradiation at energy densities lower than 0.80 J/cm2 if the substrate has been previously annealed. On the other hand, copper films deposited on as-polished substrates break up during laser processing forming copper islands.

Arf Laser Ablation of Yba2Cu3O7‐X as Studied by Emission Spectroscopy, Sem and Edax

1989 ◽  
Vol 169 ◽  
Author(s):  
Alon Hoffman ◽  
Rafael R. Manory
Keyword(s):  
Laser Ablation ◽  
Plasma Plume ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Surface Region ◽  
Fluorescence Emission Spectra ◽  
Near Surface ◽  
Spatially Resolved ◽  
Excimer Laser Irradiation ◽  
Beam Center

AbstractThe fluorescence emission spectra from the plasma plume induced by ArF excimer laser irradiation of YBa2Cu3O7‐x was studied and compared to the spectra of Y, YO, Cu, CuO, and YCuO under similar conditions. The only compound detected in the Y‐Ba‐Cu‐O ablated material spectra was YO. Spatially resolved measurements from the plasma plume emanating from the irradiated superconducting material were performed also as a function of distance from the surface.The effect of laser ablation on the morphology and composition of the irradiated YBa2Cu3O7‐x material was studied by SEM and EDAX. It was found that the 1‐2‐3 composition ratio of the near surface region was maintained after ablation. Changes in the morphology were observed in the track region and three distinctive regions could be identified as a function of distance from the beam center.

Impurity Activation in N+ Ion-Implanted 6H-SiC with Pulsed Laser Annealing Method

2000 ◽  
Vol 640 ◽  
Author(s):  
O. Eryu ◽  
K. Aoyama ◽  
K. Abe ◽  
K. Nakashima
Keyword(s):  
Contact Resistance ◽  
Laser Irradiation ◽  
Carrier Density ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Surface Region ◽  
Near Surface ◽  
Pulsed Laser Annealing ◽  
Annealing Method ◽  
Ion Implanted

ABSTRACTWe have succeeded in pulsed laser annealing of N+ ion-implanted n-type 6H-SiC for increasing the carrier density near surface in order to decrease contact resistance, which induces little redistribution of implanted impurities after laser irradiation. By repeated laser irradiation at low energy density, the ion–implanted impurities were electrically activated without melting the surface region. SiC substrates with impurity concentration of 2×1018 /cm3 were implanted with 30 keV N+ ions with dose of 4.7×1013/cm2. After pulsed laser annealing, a contact resistance was measured to be 5.7×10−5 Ωcm2 using Al electrode on the N+ -implanted layer.

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

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.

Preparation of cross-sectional samples for near-surface TEM studies

1987 ◽  
Vol 45 ◽  
pp. 380-381
Author(s):  
R.C. Dickenson ◽  
K.R. Lawless
Keyword(s):  
Standard Sample ◽  
Surface Region ◽  
Specimen Preparation ◽  
Thick Sheet ◽  
Drill Bit ◽  
Sample Holder ◽  
Metal Interface ◽  
Cross Sectional ◽  
Near Surface ◽  
Cold Worked

In thermal oxidation studies, the structure of the oxide-metal interface and the near-surface region is of great importance. A technique has been developed for constructing cross-sectional samples of oxidized aluminum alloys, which reveal these regions. The specimen preparation procedure is as follows: An ultra-sonic drill is used to cut a 3mm diameter disc from a 1.0mm thick sheet of the material. The disc is mounted on a brass block with low-melting wax, and a 1.0mm hole is drilled in the disc using a #60 drill bit. The drill is positioned so that the edge of the hole is tangent to the center of the disc (Fig. 1) . The disc is removed from the mount and cleaned with acetone to remove any traces of wax. To remove the cold-worked layer from the surface of the hole, the disc is placed in a standard sample holder for a Tenupol electropolisher so that the hole is in the center of the area to be polished.

The Effects of Ion Implantation on the Surface Features of Inconel 600

1985 ◽  
Vol 43 ◽  
pp. 288-289
Author(s):  
John D. Rubio
Keyword(s):  
Grain Boundary ◽  
Ion Implantation ◽  
Nuclear Power ◽  
Power Plants ◽  
Surface Region ◽  
Selective Dissolution ◽  
Boundary Region ◽  
Near Surface ◽  
Inconel 600 ◽  
Steam Generator Tubing

The degradation of steam generator tubing at nuclear power plants has become an important problem for the electric utilities generating nuclear power. The material used for the tubing, Inconel 600, has been found to be succeptible to intergranular attack (IGA). IGA is the selective dissolution of material along its grain boundaries. The author believes that the sensitivity of Inconel 600 to IGA can be minimized by homogenizing the near-surface region using ion implantation. The collisions between the implanted ions and the atoms in the grain boundary region would displace the atoms and thus effectively smear the grain boundary.To determine the validity of this hypothesis, an Inconel 600 sample was implanted with 100kV N2+ ions to a dose of 1x1016 ions/cm2 and electrolytically etched in a 5% Nital solution at 5V for 20 seconds. The etched sample was then examined using a JEOL JSM25S scanning electron microscope.

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