Microstructure Analysis of Thermally Stable Ohmic Contact to Both n and p+-GaAs

1992 ◽  
Vol 281 ◽  
Author(s):  
W. Y. Han ◽  
H. S. Lee ◽  
Y. Lu ◽  
M. W. Cole ◽  
L. M. Casas ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ohmic Contact ◽  
Auger Electron ◽  
Specific Contact Resistance ◽  
Thermally Stable ◽  
Depth Profiles ◽  
Transmission Electron ◽  
Specific Contact ◽  
Electron Spectrometry

ABSTRACTA thermally stable Pd/Ge/Ti/Pt/ ohmic contact with low specific contact resistance was formed on both n and p+-GaAs. The lowest specific contact resistances were 4.7×10−7 and 6.4×10−7 Ω.cm2 for the n and p+-GaAs, respectively, when the n-GaAs was doped with Si to 2×1018cm−3, and the p+-GaAs was doped with carbon to 5×1019 cm−3. Interfacial reactions and element diffusions of the contacts were investigated by using transmission electron microscopy, Auger electron spectrometry with depth profiles. All the contacts were thermally stable at 300 °C for 20 hours, and it appeared that the p-contacts were more stable than the n-contacts.

Ohmic Contacts To p+-GaAs and Al0.26Ga0.74As

1994 ◽  
Vol 337 ◽  
Author(s):  
W. Y. Han ◽  
M. W. Cole ◽  
L. M. Casas ◽  
A. DeAnni ◽  
M. Wade ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Auger Electron ◽  
Ohmic Contacts ◽  
Carbon Doped ◽  
Depth Profiles ◽  
Transmission Electron ◽  
Specific Contact ◽  
Elemental Diffusion ◽  
Electron Spectrometry

ABSTRACTOhmic contacts, with metallization scheme of Pd/Ge/Ti/Pt, were formed on heavily carbon doped GaAs and AlxGa1-xAs. The lowest specific contact resistances were 4.7x10-7 and 8.9x 10-6 Ω-cm2 for the p+-GaAs and Al0.26Ga0.74As. The p+-GaAs and Al0.26Ga0.74As were doped with carbon to 5x1019 and 2x1019 cm-3 respectively. Interfacial reactions and elemental diffusion of the contacts were investigated via transmission electron microscopy and Auger electron spectrometry with depth profiles.

Effect of Au distribution in NiO/Au film on the ohmic contact formation to p-type GaN

2005 ◽  
Vol 20 (2) ◽  
pp. 456-463 ◽  
Author(s):  
Jiin-Long Yang ◽  
J.S. Chen ◽  
S.J. Chang
Keyword(s):  
Electron Microscopy ◽  
Ohmic Contact ◽  
Incident Angle ◽  
Specific Contact Resistance ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Ohmic Behavior ◽  
Transmission Electron ◽  
Specific Contact ◽  
P Type

The distribution of Au and NiO in NiO/Au ohmic contact on p-type GaN was investigated in this work. Au (5 nm) films were deposited on p-GaN substrates by magnetron sputtering. Some of the Au films were preheated in N2 ambient to agglomerate into semi-connected structure (abbreviated by agg-Au); others were not preheated and remained the continuous (abbreviated by cont-Au). A NiO film (5 nm) was deposited on both types of samples, and all samples were subsequently annealed in N2 ambient at the temperatures ranging from 100 to 500 °C. The surface morphology, phases, and cross-sectional microstructure were investigated by scanning electron microscopy, glancing incident angle x-ray diffraction, and transmission electron microscopy. I-V measurement on the contacts indicates that only the 400 °C annealed NiO/cont-Au/p-GaN sample exhibits ohmic behavior and its specific contact resistance (ρc) is 8.93 × 10−3 Ω cm2. After annealing, Au and NiO contact to GaN individually in the NiO/agg-Au/p-GaN system while the Au and NiO layers become tangled in the NiO/cont-Au/p-GaN system. As a result, the highly tangled NiO-Au structure shall be the key to achieve the ohmic behavior for NiO/cont-Au/p-GaN system.

Reaction Kinetics of Thermally Stable Contact Metallization on 6H-SiC

2000 ◽  
Vol 640 ◽  
Author(s):  
Robert S. Okojie ◽  
Dorothy Lukco ◽  
Yuan L. Chen ◽  
David Spry ◽  
Carl Salupo
Keyword(s):  
Electron Microscopy ◽  
Titanium Silicide ◽  
Specific Contact Resistance ◽  
Thermally Stable ◽  
Platinum Silicide ◽  
Contact Metallization ◽  
Transmission Electron ◽  
Specific Contact ◽  
Reaction Zones ◽  
Kinetics Of

ABSTRACTThe growth kinetics of thermally stable Ti(100nm)/TaSi2 (200nm)/Pt (300nm) metallization on 6H-SiC was studied after heat treatment in air up to 700°C. Scanning electron microscopy (SEM) of the contact surface morphology reveals a two-dimensional network of features that is attributed to non-uniform oxide growth associated with the multigrain structure of the platinum overlayer. Auger electron spectroscopy (AES) and high-resolution transmission electron microscopy (HRTEM) identified three important reaction zones after initial 30-minute anneal at 600°C in nitrogen. One is the formation of a platinum silicide overlayer resulting from TaSi2 decomposition. The second is titanium silicide formation adjacent to the decomposed TaSi2. The third is pseudo-epitaxial Ti5Si3 at the SiC interface. Specific contact resistance values ranging from 10−4–10−6 Ω-cm2, remained stable after 200 hours at 600°C in air. Activation energies of 1.03eV for platinum silicide oxidation and 1.96eV for Ti5Si3 are obtained from Arrhenius plots.

Mechanical properties and microstructures of metal/ceramic microlaminates: Part I. Nb/MoSi2 systems

1992 ◽  
Vol 7 (10) ◽  
pp. 2765-2773 ◽  
Author(s):  
T.C. Chou ◽  
T.G. Nieh ◽  
T.Y. Tsui ◽  
G.M. Pharr ◽  
W.C. Oliver
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Elastic Moduli ◽  
Chemical Interaction ◽  
Transmission Electron ◽  
Metal Ceramic ◽  
Equal Thickness

Artificial multilayers, or microlaminates, composed of alternating layers of Nb and MoSi2 of equal thickness were synthesized by d.c., magnetron sputtering. Four different modulation wavelengths, λ, were studied: 7, 11, 20, and 100 nm. The compositions, periodicities, and microstructures of the microlaminates were characterized by Auger electron spectroscopy and transmission electron microscopy. Structural characterization revealed that the as-deposited Nb layers are polycrystalline, while the MoSi2 layers are amorphous. The hardnesses and elastic moduli of the films were measured using nanoindentation techniques. Neither a supermodulus nor a superhardness effect could be identified in the range of wavelengths investigated; for each of the microlaminates, both the hardness and modulus were found to fall between the bounds set by the properties of the monolithic Nb and MoSi2 films. Nevertheless, a modest but a measurable increase in both hardness and modulus with decreasing wavelength was observed, thus indicating that behavior cannot be entirely described by a simple rule-of-mixtures. The hardness was found to vary linearly with Δ−1/2 in a manner similar to the Hall–Petch relationship. Annealing the microlaminates at 800 °C for 90 min produces significant increases in hardness and modulus due to chemical interaction of the layers.

Sub-Micrometer Spatially Resolved Measurements of Mechanical Properties and Correlation to Microstructure and Composition

2000 ◽  
Vol 649 ◽  
Author(s):  
M. Kunert ◽  
B. Baretzky ◽  
S. P. Baker ◽  
E. J. Mittemeijer
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Measurement Techniques ◽  
Spatially Resolved ◽  
Transmission Electron ◽  
20 Nm ◽  
Almost Continuous

ABSTRACTThe variations of hardness, composition, and microstructure within a carbon implanted region – about 350 nm thick – of a Ti-6Al-4V alloy were measured using nanoindentation, Auger electron spectroscopy and transmission electron microscopy, respectively. Correlations among hardness, composition, and microstructure were made with a spatial resolution of about ±20 nm. The variation in hardness within the implanted regions was quantitatively explained as due to the formation of an almost continuous TiC layer and precipitate hardening. The problems that may arise in measuring and correlating spatial variations in such a complex material on this scale are outlined and a successful method to solve them is proposed. The need for highly spatially resolved measurement techniques is emphasized.

Comparison of Elemental Detection Using Microcalorimetry, SIMS, AES and EDS (SEM, STEM, and TEM)

2000 ◽  
Vol 6 (S2) ◽  
pp. 128-129
Author(s):  
C. B. Vartuli ◽  
F. A. Stevie ◽  
D. A. Wollman ◽  
M. Antonell ◽  
R. B. Irwin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Secondary Ion Mass Spectrometry ◽  
Transmission Electron ◽  
Cu Contamination ◽  
Scanning Transmission ◽  
Semiconductor Fabrication ◽  
Electron Spectrometry ◽  
Elemental Detection ◽  
Analytical Tools

Cu contamination has become a larger concern as more semiconductor fabrication facilities switch from aluminum to Cu interconnects. The resolution limits of several analytical tools are compared to determine the optimum analysis methods for detecting Cu contamination in semiconductor materials. The elemental detection limits of Secondary Ion Mass Spectrometry (SIMS), Auger Electron Spectrometry (AES), Microcalorimetry and Energy Dispersive Spectrometry (EDS) systems on Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM), and Transmission Electron Microscopy (TEM) instruments are evaluated for Cu in WSix.Two different samples were used in this study. One sample has a high uniform concentration (0.9% atomic, 0.7 wt.%) of Cu that was incorporated during the sputter deposition of WSi2. A lower concentration was ion implanted with 63Cu to a dose of lel4 cm-2 and has a peak concentration of lel9 cm"3, or 0.02% atomic.

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