The YBCO[001]/Ag interface: correlation between specific contact resistance and interfacial microstructure

1995 ◽  
Vol 5 (2) ◽  
pp. 2412-2415 ◽  
Author(s):  
Z.H. Gong ◽  
J.K. Grepstad ◽  
R. Fagerberg
Keyword(s):  
Contact Resistance ◽  
Interfacial Microstructure ◽  
Specific Contact Resistance ◽  
Specific Contact

Interfacial Microstructure and Carrier Conduction Process in Pt/Ti Ohmic Contact to P-In0.53Ga0.47As Formed by Rapid Thermal Processing

1990 ◽  
Vol 181 ◽  
Author(s):  
S.N.G. Chu ◽  
A. Katz ◽  
T. Boone ◽  
P.M. Thomas ◽  
V.G. Riggs ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Temperature Dependence ◽  
Contact Area ◽  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Thermionic Emission ◽  
Interfacial Microstructure ◽  
Rapid Decrease ◽  
Specific Contact Resistance ◽  
Specific Contact

ABSTRACTThe strong dependence of electrical properties of Pt/Ti ohmic contact to p–In0.53Ga0.47 As (Zn: 5 × 1018 cm−3) on the interfacial microstructure formed by rapid thermal processing (RTP) were intensively studied by transmission electron microscopy, Auger Spectroscopy, and transmission line model (TLM) measurements. The rapid decrease of the specific contact resistance with an increase in RTP temperature was correlated with the development of an interfacial reaction zone. Significant interdiffusion of Ti, In and As across the interface occurred at temperature above, 350°C for a 30 second of RTP. A minimum specific contact resistance (3.4 × 10−6 Ω-cm2) was achieved at RTP temperature of 450°C. The corresponding interfacial microstructure revealed a complicated solid state reaction zone with InAs as one of the major interfacial compounds. The low contact resistance is attributed to the carrier conduction through the InAs regions. This is also consistent with the results of Pt/Ti contact experiments to p-type InAs, InP and GaAs binary surfaces, where the lowest contact resistance was achieved on InAs (3.0 × 10−7 Ω-cm2at Zn: 5 × 1018 cm−3). The temperature dependence of specific contact resistance of as-deposited Pt/Ti contact to InGaAs agrees very well with the thermionic emission dominated carrier transport mechanism with an effective barrier height, φb, of 0.13V. The rapid decrease in the contact resistance as well as its reduced temperature dependence after RTP treatment at elevated temperatures suggesting a partial conversion of thermionic emission dominated contact area to field emission dominated regions. A phenomenological theory of multiple parrallel carrier conduction processes was proposed to analyse the temperature dependence of specific contact resistance for contacts with complicated interfacial microstructure. It was found that, for low resistance contacts, majority of the carriers conducted through only a fraction of the contact area via a tunneling mechanism.

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.

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.

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.

Ohmic Contacts to p-Type InGaAs/InP with a Graded Bandgap Heterobarrier

1993 ◽  
Vol 318 ◽  
Author(s):  
Patrick W. Leech ◽  
Geoffrey K. Reeves
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Rutherford Backscattering Spectrometry ◽  
Specific Contact Resistance ◽  
Superlattice Structure ◽  
Specific Contact ◽  
P Type ◽  
Metal Layers ◽  
Anneal Temperature ◽  
Graded Bandgap

ABSTRACTOhmic contacts to p-type InP with an In0.47Ga0.53As buffer layer and an interposed superlattice of 50 Å In0.47Ga0.53As/ 50 Å InP have been investigated. Initial studies of contacts to In0.47Ga0.53As/ InP without the superlattice structure have shown that Pd/Zn/Pd/Au metallization produced a lower specific contact resistance (pc = 1.1 × 10−4 Ω cm2) than Pd/Ge/Au, and over a wider range of anneal temperature than Au/Zn/Au. The incorporation of the superlattice in the p-In0.47Ga0.53As/ InP structure resulted in Pd/Zn/Pd/Au contacts with pc of 3.2 × 10−5 Ω cm2 as-deposited and 7.5 × 10−6 Ω.cm2 after a 500 °C anneal. The presence of Pd/Zn in the metallization was shown as important in reducing pc. Significant intermixing of the metal layers and In0.47Ga0.53As occured at ≥ 350 °C, as revealed by Rutherford backscattering spectrometry.

scholarly journals Contact Resistance of InGaN/GaN Light Emitting Diodes Grown on the Production Model Multi-Wafer MOVPE Reactor

1999 ◽  
Vol 4 (S1) ◽  
pp. 703-708 ◽  
Author(s):  
R.W. Chuang ◽  
A.Q. Zou ◽  
H.P. Lee ◽  
Z.J. Dong ◽  
F.F. Xiong ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Transmission Line ◽  
Device Fabrication ◽  
Production Model ◽  
Specific Contact Resistance ◽  
Single Quantum Well ◽  
Light Emitting ◽  
Annealing Temperatures ◽  
Line Measurement ◽  
Specific Contact

We report both the device fabrication and characterization of InGaN/GaN single quantum well LEDs grown on sapphire substrates using multi-wafer MOVPE reactor. To improve current spreading of the LEDs, a self-aligned process is developed to define LED mesa that is coated with a thin, semi-transparent Ni/Au (40 Å/40 Å) layer. A detailed study on the ohmic contact resistance of Ni/Cr/Au on p-GaN versus annealing temperatures is carried out on transmission line test structures. It was found that the annealing temperatures between 300 to 500 °C yield the lowest specific contact resistance rc ( 0.016 Ω-cm2 at a current density of 66.7 mA/cm). Based on the extracted rc from the transmission line measurement, we estimate that the contact resistance of the p-type GaN accounts for ∼ 88% of the total series resistance of the LED.

scholarly journals Behavior of W and WSix Contact Metallization on n- and p- Type GaN

1999 ◽  
Vol 4 (S1) ◽  
pp. 684-690
Author(s):  
X. A. Cao ◽  
F. Ren ◽  
J. R. Lothian ◽  
S. J. Pearton ◽  
C. R. Abernathy ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Annealing Temperature ◽  
Specific Contact Resistance ◽  
Ohmic Behavior ◽  
Contact Metallization ◽  
Specific Contact ◽  
Heavily Doped ◽  
Sputter Deposited ◽  
Optimum Annealing Temperature ◽  
P Type

Sputter-deposited W-based contacts on p-GaN (NA∼1018 cm−3) display non-ohmic behavior independent of annealing temperature when measured at 25°C. The transition to ohmic behavior occurs above ∼250°C as more of the acceptors become ionized. The optimum annealing temperature is ∼700°C under these conditions. These contacts are much more thermally stable than the conventional Ni/Au metallization, which shows a severely degraded morphology even at 700°C. W-based contacts may be ohmic as-deposited on very heavily doped n-GaN, and the specific contact resistance improves with annealing up to ∼900°C.

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