Diffusion and Subsurface Bonding of Hydrogen in Silicon

1987 ◽  
Vol 104 ◽  
Author(s):  
A. E. Jaworowski ◽  
L. S. Wielunski

ABSTRACTThe hydrogen depth profiling in the near-surface region in silicon reveals the existence of a subsurface hydrogen layer. This layer acts as a barrier to diffusion. The observed subsurface hydrogen profile rises and then drops off sharply with increasing depth and is stable up to 770 K. Our annealing data indicate a rather complex motion of monatomic and molecular hydrogen in the near-surface region (<1500 A) in the temperature range 300 – 800 K. The subsurface molecule formation represents the dominant hydrogen trapping process in silicon.

1985 ◽  
Vol 59 ◽  
Author(s):  
A. E. Jaworowski ◽  
L. S. Wielunski ◽  
G. Bambakidis

ABSTRACTThe near-surface hydrogen profile was measured using the 15N hydrogen profiling technique in silicon. By depositing an adlayer of Al on the surface we were able to observe the separation of the near-surface hydrogen profile in silicon from the surface contamination layer. The hydrogen profiling of the near-surface region revealed the existence of a subsurface hydrogen layer which acts as a barrier to the transfer of hydrogen into the bulk. The observed subsurface layer is saturated with molecular hydrogen and its profile drops off sharply with increasing depth. The structure of this molecular hydrogen barrier and its thermal stability were studied.


1981 ◽  
Vol 11 ◽  
Author(s):  
Patrick Trocellier ◽  
Bernard Nens ◽  
Charles Engelmann

The Rutherford backscattering technique is useful for the determination of the concentration profiles of some heavy elements in the near surface region of glasses, but is not able to provide chemical information on the elements detected.


1988 ◽  
Vol 129 ◽  
Author(s):  
S. J. Pearton ◽  
K. S. Jones ◽  
U. K. Chakabarti ◽  
B. Emerson ◽  
E. Lane ◽  
...  

ABSTRACTThe etch rate of GaAs and AIGaAs during CC12F2:O2 reactive ion etching was measured over the temperature range 50–400ºC. For GaAs, the etch rate increases super-linearly from ∼400Å.min−1 to ∼3000Åmin−1 over this temperature range for a 0.56 W.cm−2, 4 mTorr discharge with a 19:1 CC12F2:O2 mixture. The surface morphology of GaAs undergoes a smooth-to-rough transition near 150ºC, and theresidual damage in the near-surface region appears to decrease with increasing etch temperature. The I-V characteristics of Schottky diodes fabricated on the etched surfaces show ideality factors of 1.001 for 150ºC RIE, although these worsen because of thermal degradation of higher etching temperatures. From AES and XPS data the etched GaAs shows little contamination after etching. In contrast, little temperature dependence of the etch rate of AIGaAs is observed using CC12F2:O2, although once again there is surface degradation for etching temperatures above 150ºC.


1995 ◽  
Vol 395 ◽  
Author(s):  
Dirk Freundt ◽  
Georg Landmesser ◽  
Angela Rizzi ◽  
Hans Lüth

ABSTRACTThe surface chemistry of Triallylamine (TAA), (C3H5)3N on Si(111) has been studied by adsorption under UHV conditions and in-situ characterization. High Resolution Electron Energy Loss Spectroscopy (HREELS) yields the spectrum of vibration modes at the surface, and X-ray Photoelectron Spectroscopy (XPS) yields the chemical bonding and the partial concentration of the different adsorbates in the near surface region. The tertiary amine TAA physisorbs at RT without dissociation. Successive annealing steps of the physisorbed phase induce the dissociation of the amine at 400 °C. At higher temperatures the allyl groups are partially desorbed and the rest fully dissociated at 600 °C, where the hydrogen leaves the surface and the nitrogen and carbon start to diffuse into the Si substrate. A very similar behaviour is observed for the adsorption of TAA on a heated Si substrate. The coadsorption with Triethylgallium (TEG) in the temperature range 500–800 °C does not induce significant changes in the reaction at the Si surface. A negligible quantity of Ga is detected at the surface after codeposition in the whole investigated temperature range. The growth of a GaN phase has not been observed, neither on Si(111) nor on Al2O3(0001) substrates.


2003 ◽  
Vol 18 (1) ◽  
pp. 173-179 ◽  
Author(s):  
Maxim B. Kelman ◽  
Paul C. McIntyre ◽  
Bryan C. Hendrix ◽  
Steven M. Bilodeau ◽  
Jeffrey F. Roeder ◽  
...  

Structural properties of polycrystalline Pb(Zr0.35Ti0.65)O3 (PZT) thin films grown by metalorganic chemical vapor deposition on Ir bottom electrodes were investigated. Symmetric x-ray diffraction measurements showed that as-deposited 1500 íthick PZT films are partially tetragonal and partially rhombohedral. Cross-section scanning electron microscopy showed that these films have a polycrystalline columnar microstructure with grains extending through the thickness of the film. X-ray depth profiling using the grazing-incidence asymmetric Bragg scattering geometry suggests that each grain has a bilayer structure consisting of a near-surface region in the etragonal phase and the region at the bottom electrode interface in the rhombohedral hase. The required compatibility between the tetragonal and rhombohedral phases in he proposed layered structure of the 1500 Å PZT can explain the peak shifts observed n the symmetric x-ray diffraction results of thicker PZT films.


Author(s):  
R.C. Dickenson ◽  
K.R. Lawless

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.


Author(s):  
John D. Rubio

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.


Author(s):  
S. Cao ◽  
A. J. Pedraza ◽  
L. F. Allard

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.


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