The Relationship Between Microstructure and Contact Resistance in NiAuGe/ZrB2/Au Ohmic Contacts to GaAs.

1990 ◽  
Vol 181 ◽  
Author(s):  
M. P. Grimshaw ◽  
A. E. Staton-Bevan ◽  
J. Herniman ◽  
D. A. Allan
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Gaas Layer ◽  
Contact System ◽  
Initial Contact ◽  
The Relationship ◽  
Resistance Data

ABSTRACTThe microstructure and contact resistance of NiAuGe contacts to n-type GaAs were determined as a function of initial contact composition. The contact microstructures were found to contain varying amounts of of α, α’ and β (or Au7Ga2) Au-Ga, epitaxial Ge, NiGe and NiGeAs phases. A previously unidentified NiAsx (Zr,B) phase was also observed. The contact resistance was found to vary between 0.22-0.38±0.03Ωmm. Comparison of the microstructural and contact resistance data revealed that the ohmic formation models based on (i) the formation of a recrystallised n+ GaAs layer and (ii) the presence of a graded Ge/GaAs heterojunction were not applicable to this contact system.

Microstructural Characterization of Au-Ge-Ni based ohmic contacts to GaAs/AlGaAs modfet device

1987 ◽  
Vol 45 ◽  
pp. 326-327
Author(s):  
A.K. Rai ◽  
A.K. Petford-Long ◽  
A. Ezis ◽  
D.W. Langer
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Microstructural Characterization ◽  
Almost Everywhere ◽  
Spacer Layer ◽  
Good Contact ◽  
The Relationship ◽  
Lower Contact

Considerable amount of work has been done in studying the relationship between the contact resistance and the microstructure of the Au-Ge-Ni based ohmic contacts to n-GaAs. It has been found that the lower contact resistivity is due to the presence of Ge rich and Au free regions (good contact area) in contact with GaAs. Thus in order to obtain an ohmic contact with lower contact resistance one should obtain a uniformly alloyed region of good contact areas almost everywhere. This can possibly be accomplished by utilizing various alloying schemes. In this work microstructural characterization, employing TEM techniques, of the sequentially deposited Au-Ge-Ni based ohmic contact to the MODFET device is presented.The substrate used in the present work consists of 1 μm thick buffer layer of GaAs grown on a semi-insulating GaAs substrate followed by a 25 Å spacer layer of undoped AlGaAs.

The Stability to Ageing of Pd/Zn and Pt-Based Ohmic Contacts to p-InGaAs/InP

1998 ◽  
Vol 514 ◽  
Author(s):  
P. W. Leech ◽  
G. K. Reeves ◽  
P. Ressel
Keyword(s):  
Contact Resistance ◽  
Barrier Layer ◽  
Ohmic Contacts ◽  
Rutherford Backscattering Spectrometry ◽  
Rutherford Backscattering ◽  
Contact System ◽  
Specific Contact Resistance ◽  
Barrier Layers ◽  
Specific Contact ◽  
The Stability

ABSTRACTPd/Zn/Au contacts to p-In0.53Ga0.47As/InP with various barrier layers (Pd, Pt or LaB,) to the indiffusion of Au have been examined by Rutherford Backscattering Spectrometry (RBS). For the metallisations with a barrier layer of Pd, the ageing of the contacts at 400°C for 20 h produced a widespread indiffusion of Au. In comparison, the incorporation of a layer of Pt or amorphous LaB6 prevented an indiffusion of Au and significantly reduced any outdiffusion of the semiconductor elements. The presence of the barrier layer of Pt or LaB6 produced little or no detrimental increase in specific contact resistance, ρc, for this contact system. Values of ρc in the range 8–10 × 10−6 Ω cm2 were obtained for all of the contacts based on Pd/Zn/Au after annealing at 500°C. A comparison has been made with the characteristics of Pt/Ti/Pt/Au contacts to p-In0.53Ga0.47As/ InP which were shown as stable against the indiffusion of Au.

TEM Studies and Contact Resistance of Au/Ni/Ti/Ta/n-GaN Ohmic Contacts

2003 ◽  
Vol 764 ◽  
Author(s):  
D.N. Zakharov ◽  
Z. Liliental-Weber ◽  
A. Motayed ◽  
S.N. Mohammad
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
High Resolution Electron Microscopy ◽  
X Ray ◽  
Electron Energy Loss Spectrometry ◽  
Resolution Electron ◽  
Order Of Magnitude ◽  
Contact Surfaces ◽  
Electron Energy Loss ◽  
Magnitude Difference

AbstractOhmic Ta/Ti/Ni/Au contacts to n-GaN have been studied using high resolution electron microscopy (HREM), energy dispersive X-ray spectrometry (EDX) and electron energy loss spectrometry (EELS). Two different samples were used: A - annealed at 7500C withcontact resistance 5×10-6 Ω cm2 and B-annealed at 7750C with contact resistance 6×10-5 Ω cm2. Both samples revealed extensive in- and out-diffusion between deposited layers with some consumption ofGaNlayerand formation of TixTa1-xN50 (0<x<25) at the GaN interface. Almost an order of magnitude difference in contact resistances can be attributed to structure and chemical bonding of Ti-O layers formed on the contact surfaces.

Backside FIB Device Modifications Through the BOX Layer of an SOI Device

2002 ◽  
Author(s):  
Jeffery P. Huynh ◽  
Joseph P. Shannon ◽  
Richard W. Johnson ◽  
Mike Santana ◽  
Thomas Y. Chu ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Oxide Layer ◽  
Cross Section ◽  
Test Structure ◽  
Ring Oscillator ◽  
Oscillator Circuit ◽  
Entire Process ◽  
Oscillator Frequency ◽  
Polysilicon Gate ◽  
Resistance Data

Abstract Modifications directly to a transistor’s source/drain and polysilicon gate through the backside of a SOI device were made. Contact resistance data was obtained by creating contacts through the buried oxide layer of a manufactured test structure. A ring oscillator circuit was modified and the shift in oscillator frequency was measured. Finally, cross section images of the FIB created contacts were presented in the paper to illustrate the entire process.

Improvement of the Specific Contact Resistance on P-Type 4H-SiC by Using a Highly P-Typed Doped 4H-SiC Layer Selectively Grown by VLS Transport

2014 ◽  
Vol 806 ◽  
pp. 57-60
Author(s):  
Nicolas Thierry-Jebali ◽  
Arthur Vo-Ha ◽  
Davy Carole ◽  
Mihai Lazar ◽  
Gabriel Ferro ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Schottky Barrier Height ◽  
Annealing Temperature ◽  
Process Condition ◽  
Specific Contact Resistance ◽  
High Doping Level ◽  
Annealing Temperatures ◽  
Specific Contact ◽  
P Type

This work reports on the improvement of ohmic contacts made on heavily p-type doped 4H-SiC epitaxial layer selectively grown by Vapor-Liquid-Solid (VLS) transport. Even before any annealing process, the contact is ohmic. This behavior can be explained by the high doping level of the VLS layer (Al concentration > 1020 cm-3) as characterized by SIMS profiling. Upon variation of annealing temperatures, a minimum value of the Specific Contact Resistance (SCR) down to 1.3x10-6 Ω.cm2 has been obtained for both 500 °C and 800 °C annealing temperature. However, a large variation of the SCR was observed for a same process condition. This variation is mainly attributed to a variation of the Schottky Barrier Height.

Ohmic Contacts to GaAs

1982 ◽  
Vol 18 ◽  
Author(s):  
Norman Braslau
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Spatially Inhomogeneous ◽  
Heavily Doped

The present capability of obtaining ohmic contacts to GaAs over a range of doping levels is reviewed. Possible models of transport across the metalsemiconductor interface are discussed and contact techniques are described. The widely used Au—Ge alloyed contact is seen to have a spatially inhomogeneous interface which appears to control its contact resistance. The most satisfactory process at this time is to alloy into a previously fabricated heavily doped layer.

Current Transport in Ti/Al/Ni/Au Ohmic Contacts to GaN and AlGaN

2007 ◽  
Vol 556-557 ◽  
pp. 1027-1030 ◽  
Author(s):  
Ferdinando Iucolano ◽  
Fabrizio Roccaforte ◽  
Filippo Giannazzo ◽  
A. Alberti ◽  
Vito Raineri
Keyword(s):  
Contact Resistance ◽  
Field Emission ◽  
Ohmic Contacts ◽  
Theoretical Models ◽  
Specific Contact Resistance ◽  
Strong Increase ◽  
Current Transport ◽  
Electrical Characteristics ◽  
Structural And Electrical Properties ◽  
Specific Contact

In this work, the structural and electrical properties of Ti/Al/Ni/Au contacts on n-type Gallium Nitride were studied. An ohmic behaviour was observed after annealing above 700°C. The structural analysis showed the formation of an interfacial TiN layer and different phases in the reacted layer (AlNi, AlAu4, Al2Au) upon annealing. The temperature dependence of the specific contact resistance demonstrated that the current transport occurs through thermoionic field emission in the contacts annealed at 600°C, and field emission after annealing at higher temperatures. By fitting the data with theoretical models, a reduction of the Schottky barrier from 1.21eV after annealing at 600°C to 0.81eV at 800°C was demonstrated, together with a strong increase of the carrier concentration at the interface. The reduction of the contact resistance upon annealing was discussed by correlating the structural and electrical characteristics of the contacts.

Ohmic contacts to pseudomorphic HEMTs with low contact resistance due to enhanced Ge penetration through AlGaAs layers

2008 ◽  
Vol 23 (2) ◽  
pp. 025019 ◽  
Author(s):  
G Sai Saravanan ◽  
K Mahadeva Bhat ◽  
K Muraleedharan ◽  
H P Vyas ◽  
R Muralidharan ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts

scholarly journals Relationship Between 2-Dimensional Frontal Plane Measures and the Knee Abduction Angle During the Drop Vertical Jump

2019 ◽  
Vol 28 (4) ◽  
Author(s):  
Brad W. Willis ◽  
Katie Hocker ◽  
Swithin Razu ◽  
Aaron D. Gray ◽  
Marjorie Skubic ◽  
...  
Keyword(s):  
Motion Capture ◽  
Vertical Jump ◽  
Frontal Plane ◽  
Ligament Injury ◽  
Coefficient Of Determination ◽  
Abduction Angle ◽  
Initial Contact ◽  
Knee Abduction ◽  
The Relationship ◽  
Drop Vertical Jump

Context: Knee abduction angle (KAA), as measured by 3-dimensional marker-based motion capture systems during jump-landing tasks, has been correlated with an elevated risk of anterior cruciate ligament injury in females. Due to the high cost and inefficiency of KAA measurement with marker-based motion capture, surrogate 2-dimensional frontal plane measures have gained attention for injury risk screening. The knee-to-ankle separation ratio (KASR) and medial knee position (MKP) have been suggested as potential frontal plane surrogate measures to the KAA, but investigations into their relationship to the KAA during a bilateral drop vertical jump task are limited. Objective: To investigate the relationship between KASR and MKP to the KAA during initial contact of the bilateral drop vertical jump. Design: Descriptive. Setting: Biomechanics laboratory. Participants: A total of 18 healthy female participants (mean age: 24.1 [3.88] y, mass: 65.18 [10.34] kg, and height: 1.63 [0.06] m). Intervention: Participants completed 5 successful drop vertical jump trials measured by a Vicon marker-based motion capture system and 2 AMTI force plates. Main Outcome Measure: For each jump, KAA of the tibia relative to the femur was measured at initial contact along with the KASR and MKP calculated from planar joint center data. The coefficient of determination (r2) was used to examine the relationship between the KASR and MKP to KAA. Results: A strong linear relationship was observed between MKP and KAA (r2 = .71), as well as between KASR and KAA (r2 = .72). Conclusions: Two-dimensional frontal plane measures show strong relationships to the KAA during the bilateral drop vertical jump.

Modelling Geometrical Effects of Parasitic and Contact Resistance of FET Devices

1996 ◽  
Vol 427 ◽  
Author(s):  
Geoffrey K. Reeves ◽  
H. Barry Harrison ◽  
Patrick W. Leech
Keyword(s):  
Contact Resistance ◽  
Material Properties ◽  
Ohmic Contacts ◽  
Difficult Problem ◽  
Specific Contact Resistance ◽  
Metal Silicide ◽  
Transmission Line Model ◽  
Specific Contact ◽  
Geometrical Effects ◽  
Contact Parameters

AbstractThe continual trend in decreasing the dimensions of semiconductor devices results in a number of technological problems. One of the more significant of these is the increase in contact resistance, Rc. In order to understand and counteract this increase, Rc needs to be quantitatively modelled as a function of the geometrical and material properties of the contact. However the use of multiple semiconductor layers for ohmic contacts makes the modelling and calculation of Rc a more difficult problem. In this paper, a Tri-Layer Transmission Line Model (TLTLM) is used to analyse a MOSFET ohmic contact and gatedrain region. A quantitative assessment of the influence on Rc of important contact parameters such as the metal-silicide specific contact resistance, the silicide-silicon specific contact resistance and the gate-drain length can thus be made. The paper further describes some of the problems that may be encountered in defining Rc when the dimensions of certain types of contact found in planar devices decrease.

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