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.

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.

Transmission electron microscopy assessment of the Si enhancement of Ti∕Al∕Ni∕Au Ohmic contacts to undoped AlGaN∕GaN heterostructures

2006 ◽  
Vol 100 (3) ◽  
pp. 034904 ◽  
Author(s):  
Vincent Desmaris ◽  
Jin-Yu Shiu ◽  
Chung-Yu Lu ◽  
Niklas Rorsman ◽  
Herbert Zirath ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ohmic Contacts ◽  
Transmission Electron

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.

Sign in / Sign up

Export Citation Format

Share Document