A microstructural and electrical investigation of Pd/Ge/Ti/Au ohmic contact to n-type GaAs

1996 ◽  
Vol 427 ◽  
Author(s):  
J. S. Kwak ◽  
H. K. Baik ◽  
H. Kim ◽  
J. -L. Lee ◽  
D. W. Shin ◽  
...  
Keyword(s):  
Ohmic Contact ◽  
Gaas Substrate ◽  
Isothermal Annealing ◽  
Interfacial Microstructure ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Electrical Investigation ◽  
Transmission Electron ◽  
Elemental Diffusion

AbstractInterfacial microstructure and elemental diffusion of Pd/Ge/Ti/Au ohmic contact to n-type GaAs have been investigated using x-ray diffraction(XRD), Auger electron spectroscopy(AES), and cross-sectional transmission electron microscopy(XTEM), and their results are used to interpret the electrical properties. The lowest contact resistance of 0.43 Ωmm is obtained after annealing at 380°C. The contact is thermally stable even after isothermal annealing for 5h at 400°C. The good Pd/Ge/Ti/Au ohmic contact is due to the formation of both AuGa and TiO compounds. The AuGa compound enhances the creation of more Ga vacancies, followed by incorporation of Ge into Ga vacancies and TiO compound suppresses As outdiffusion from GaAs substrate, respectively.

Cross-Sectional TEM Study Of Phase Separation In Reaction Of Ni-Ta Films With GaAs

1985 ◽  
Vol 54 ◽  
Author(s):  
A. Lahav ◽  
M. Eizenberg ◽  
Y. Komem
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Transmission Electron Microscopy ◽  
Phase Separation ◽  
Gaas Substrate ◽  
Auger Spectroscopy ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron

ABSTRACTThe reaction between Ni60Ta40 amorphous alloy and (001) GaAs was studied by cross-sectional transmission electron microscopy, Auger spectroscopy, and x-ray diffraction. At 400°C formation of Ni GaAs at the interface with GaAs was observed. After heat treatment at 600°C in vacuum a layered structure of TaAs/NiGa/GaAs has been formed. The NiGa layer has epitaxial relations to the GaAs substrate. The vertical phase separation can be explained by opposite diffusion directions of nickel and arsenic atoms.

Microstructural study of MBE-grown ZnO film on GaN/sapphire (0001) substrate

Open Physics ◽  
2008 ◽  
Vol 6 (3) ◽  
Author(s):  
Hua Li ◽  
Jianping Sang ◽  
Chang Liu ◽  
Hongbing Lu ◽  
Juncheng Cao
Keyword(s):  
Interface Layer ◽  
Interfacial Microstructure ◽  
X Ray Diffraction ◽  
Zno Film ◽  
Epitaxial Relationship ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Gan Heterostructure

AbstractSingle crystalline ZnO film is grown on GaN/sapphire (0001) substrate by molecular beam epitaxy. Ga2O3 is introduced into the ZnO/GaN heterostructure intentionally by oxygen-plasma pre-exposure on the GaN surface prior to ZnO growth. The crystalline orientation and interfacial microstructure are characterized by X-ray diffraction and transmission electron microscopy. X-ray diffraction analysis shows strong c-axis preferred orientation of the ZnO film. Cross-sectional transmission electron microscope images reveal that an additional phase is formed at the interface of ZnO/GaN. Through a comparison of diffraction patterns, we confirm that the interface layer is monoclinic Ga2O3 and the main epitaxial relationship should be $$ (0001)_{ZnO} \parallel (001)_{Ga_2 O_3 } \parallel (0001)_{GaN} $$ and $$ [2 - 1 - 10]_{ZnO} \parallel [010]_{Ga_2 O_3 } \parallel [2 - 1 - 10]_{GaN} $$.

Interfacial Reactions of Nickel films on GaAs

1983 ◽  
Vol 31 ◽  
Author(s):  
L.J. Chen ◽  
Y.F. Hsieh
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gaas Substrate ◽  
Isothermal Annealing ◽  
Morphological Structure ◽  
Interfacial Reactions ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
X Ray ◽  
Transmission Electron

ABSTRACTTransmission electron microscopy (TEM) and X-ray diffraction (XRD) were performed to study the interfacial reactions of Ni/GaAs contact system as a result of isothermal annealing and two step annealing. Ni2GaAs was observed to exhibit preferred orientation relationships with respect to GaAs substrate after 300–350°C annealing. The compound decomposed to NiAs and Ga-compounds after 400°C annealing. NiAs was also found to grow preferentially on GaAs. The step annealing was found to be ineffective in varying the morphological structure of interface.

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.

InAs Quantum Dots Grown on an AlGaAsSb Strain-Relief Buffer

2000 ◽  
Vol 642 ◽  
Author(s):  
A.L. Gray ◽  
L. R. Dawson ◽  
Y. Lin ◽  
A. Stintz ◽  
Y.-C. Xin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cross Section ◽  
Gaas Substrate ◽  
Buffer Layers ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Strain Relief ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Transmission Electron

ABSTRACTAn In(Ga)As-based self-assembled quantum dot laser test structure grown on strain-relief Al0.5Ga0.5As1-ySby strain-relief buffer layers (0≤y ≤ 0.24) on a GaAs substrate is investigated in an effort to increase dot size and therefore extend the emission wavelength over conventional InAs quantum dots on GaAs platforms. Cross-section transmission electron microscopy, and high-resolution x-ray diffraction are used to monitor the dislocation filtering process and morphology in the buffer layers. Results show that the buffer layers act as an efficient dislocation filter by drastically reducing threading dislocations, thus providing a relaxed, low dislocation, compositionally modulated Al0.5Ga0.5Sb0.24As0.76 substrate for large (500Å height x 300Å width) defect -free InAs quantum dots. Photoluminescence shows a ground-state emission of the InAs quantum dots at 1.45 μm.

scholarly journals The Reliability Improvement of Cu Interconnection by the Control of Crystallizedα-Ta/TaNxDiffusion Barrier

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Wei-Lin Wang ◽  
Chia-Ti Wang ◽  
Wei-Chun Chen ◽  
Kuo-Tzu Peng ◽  
Ming-Hsin Yeh ◽  
...  
Keyword(s):  
Diffusion Barrier ◽  
Practical Application ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Reliability Improvement ◽  
N Concentration ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Interconnection Structure

Ta/TaN bilayers have been deposited by a commercial self-ionized plasma (SIP) system. The microstructures of Ta/TaN bilayers have been systematically characterized by X-ray diffraction patterns and cross-sectional transmission electron microscopy. TaN films deposited by SIP system are amorphous. The crystalline behavior of Ta film can be controlled by the N concentration of underlying TaN film. On amorphous TaN film with low N concentration, overdeposited Ta film is the mixture ofα- andβ-phases with amorphous-like structure. Increasing the N concentration of amorphous TaN underlayer successfully leads upper Ta film to form pureα-phase. For the practical application, the electrical property and reliability of Cu interconnection structure have been investigated by utilizing various types of Ta/TaN diffusion barrier. The diffusion barrier fabricated by the combination of crystallizedα-Ta and TaN with high N concentration efficiently reduces the KRc and improves the EM resistance of Cu interconnection structure.

Evolution of Epitaxial SixGei1-x Alloys on Si(100) During Thermal Annealing a-Ge/Au Bilayers Deposited on Si Substrate

1992 ◽  
Vol 280 ◽  
Author(s):  
Z. Ma ◽  
L. H. Allen
Keyword(s):  
Single Crystal ◽  
Thermal Annealing ◽  
Rutherford Backscattering Spectrometry ◽  
Solid Phase ◽  
Growth Dynamics ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron

ABSTRACTSolid phase epitaxial (SPE) growth of SixGei1-x alloys on Si (100) was achieved by thermal annealing a-Ge/Au bilayers deposited on single crystal Si substrate in the temperature range of 280°C to 310°C. Growth dynamics was investigated using X-ray diffraction, Rutherford backscattering spectrometry, and cross-sectional transmission electron microscopy. Upon annealing, Ge atoms migrate along the grain boundaries of polycrystalline Au and the epitaxial growth initiates at localized triple points between two Au grains and Si substrate, simultaneously incorporating a small amount of Si dissolved in Au. The Au is gradually displaced into the top Ge layer. Individual single crystal SixGei1-x islands then grow laterally as well as vertically. Finally, the islands coalesce to form a uniform layer of epitaxial SixGe1-x alloy on the Si substrate. The amount of Si incorporated in the final epitaxial film was found to be dependent upon the annealing temperature.

A structural analysis of the Pd/GaN ohmic contact annealing behavior

2002 ◽  
Vol 743 ◽  
Author(s):  
C. C. Kim ◽  
P. Ruterana ◽  
J. H. Je
Keyword(s):  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Structural Evolution ◽  
Electron Beam Evaporation ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
Annealing Behavior ◽  
X Ray ◽  
Transmission Electron ◽  
The Relationship

AbstractFor ohmic contact on p GaN, palladium is one of the best candidates showing ohmic characteristics already without annealing. To be realized in devices, it is necessary to know the behavior of the ohmic contacts at accelerated conditions, especially for high temperatures and power. We report on the structural evolution of palladium layers (30 nm) deposited on GaN (0001) by electron beam evaporation without intentional annealing. They were next cut into various pieces which were individually submitted to rapid thermal annealing at 400, 500, 600, 700 and 800°C for 10 sec. We investigate the differences in the microstructure and the location of interfacial phases and their relationships as determined by X-ray diffraction and transmission electron microscopy, we then suggest the formation mechanism based on the relationship. It is shown that the interface is disrupted at annealing above 600°C and by 800°C only very small patches of Pd are still present, however they area completely imbedded in a matrix of intermetallic phases (gallides) formed by the reaction with GaN.

Evolution of Nanoindentation Hardness of Fe/Cu Nanometer-Scale Multilayers by Magnetron Sputtering

2008 ◽  
Vol 373-374 ◽  
pp. 104-107 ◽  
Author(s):  
J. Gao ◽  
Z.L. Wu ◽  
Z.P. Zhang ◽  
B.S. Cao ◽  
M.K. Lei
Keyword(s):  
Magnetron Sputtering ◽  
Nanometer Scale ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron ◽  
Modulus Difference ◽  
Nanoindentation Hardness ◽  
Modulation Wavelength ◽  
Peak Value

Fe/Cu nanometer-scale multilayers with nominal modulation wavelengths ranging from 5 to 40 nm are deposited by direct current magnetron sputtering on Si (100) substrates. Modulation structures of the multilayers are examined by small angle / wide angle x-ray diffraction (SA/WAXRD) and cross-sectional transmission electron microscopy (XTEM). Hardness of the multilayers is measured by using nanoindentation. All the multilayers have Fe (110) and Cu (111) textures. Interface coherency is observed in the multilayers with designed modulation wavelengths of 5 and 10 nm. The hardness increases firstly and then deceases with increasing the modulation wavelength, and reaches peak value of 7.29±0.29 GPa in the multilayers with nominal modulation wavelength of 10 nm. The evolution of the hardness of the mulitlayers is explained by interface width and modulus difference between sublayers.

scholarly journals Structural Property Study for GeSn Thin Films

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3645
Author(s):  
Liyao Zhang ◽  
Yuxin Song ◽  
Nils von den Driesch ◽  
Zhenpu Zhang ◽  
Dan Buca ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron

The structural properties of GeSn thin films with different Sn concentrations and thicknesses grown on Ge (001) by molecular beam epitaxy (MBE) and on Ge-buffered Si (001) wafers by chemical vapor deposition (CVD) were analyzed through high resolution X-ray diffraction and cross-sectional transmission electron microscopy. Two-dimensional reciprocal space maps around the asymmetric (224) reflection were collected by X-ray diffraction for both the whole structures and the GeSn epilayers. The broadenings of the features of the GeSn epilayers with different relaxations in the ω direction, along the ω-2θ direction and parallel to the surface were investigated. The dislocations were identified by transmission electron microscopy. Threading dislocations were found in MBE grown GeSn layers, but not in the CVD grown ones. The point defects and dislocations were two possible reasons for the poor optical properties in the GeSn alloys grown by MBE.

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