Pd/Ge Contacts to n-TYPE InP

1993 ◽  
Vol 300 ◽  
Author(s):  
Ping Jian ◽  
Douglas G. Ivey ◽  
Robert Bruce ◽  
Gordon Knight
Keyword(s):  
Contact Resistance ◽  
Amorphous Phase ◽  
Surface Region ◽  
Electron Beam Evaporation ◽  
Phase Changes ◽  
Specific Contact Resistance ◽  
Transmission Electron ◽  
Specific Contact ◽  
Different Thickness ◽  
Inp Surface

ABSTRACTMultilayer metallizations of Pd/Ge/Pd, with different thickness ratios of Ge and Pd, were deposited onto n-type InP by means of electron beam evaporation. The specimens were then annealed in flowing N2 gas at temperatures ranging from 250 to 425°C for various times. Transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDX) and electron diffraction were used to identify the phase changes during reaction. The four point probe method was used for electrical resistance measurements. A Pd-In-P amorphous phase and a Pd2Ge compound formed during deposition. Subsequent annealing resulted in crystallization of the amorphous phase followed by epitaxial growth of Pd2InP(II) on InP at 350°C. At 425°C, Pd2InP(II) with Ge in solution, decomposed producing a contact with a lower specific contact resistance. The lowest contact resistances achieved were ∼10−5 Ωcm2. Further annealing led to more decomposition of InP, including presumably the Ge doped InP surface region, which corresponded to an increase in contact resistance.

Electrical & Structural Properties of TiSi2 Films

1988 ◽  
Vol 116 ◽  
Author(s):  
N.M. Ravindra ◽  
T. Fink ◽  
R.P. Moerkirk ◽  
D. Fathy
Keyword(s):  
Contact Resistance ◽  
Structural Properties ◽  
Specific Contact Resistance ◽  
Electrical Measurements ◽  
Temperature Dependent ◽  
Measurement Temperature ◽  
Transmission Electron ◽  
Device Structures ◽  
Specific Contact ◽  
Ti Films

AbstractStudies of the electrical and structural properties of TiSi2 films formed during the fabrication of shallow junctions by ion implanting As+ into p–Si through Ti films are reported here. Electrical measurements of the temperature dependent specific contact resistance and structural measurements such as transmission electron microscopy have been performed on these device structures. The specific contact resistance is seen to decrease with increasing measurement temperature. These studies have been carried out on furnace and rapid thermally annealed films.

Formation of Ni/Pt/Au Ohmic Contacts to p-GaN

1997 ◽  
Vol 482 ◽  
Author(s):  
Ja-Soon Jang ◽  
Hyo-Gun Kim ◽  
Kyung-Hyun Park ◽  
Chang-Sub Um ◽  
Il-Ki Han ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Chemical Vapor ◽  
Electron Beam Evaporation ◽  
Specific Contact Resistance ◽  
Metal Thin Films ◽  
Linear Behavior ◽  
Specific Contact ◽  
P Type

AbstractWe report a new Ni/Pt/Au (20/30/80 nm) metallization scheme to achieve a low ohmic contacts to p-type GaN with a carrier concentration of 9.4 × 1016 cm-3. A Mg-doped GaN layer (0.5 μm) was grown on (0001) sapphire substrate by metalorganic chemical vapor deposition (MOCVD). All metal thin films were deposited on the p-GaN layer in an electron-beam evaporation system. Samples were annealed by a rapid thermal annealing (RTA) process at a range of temperatures from 300 °C to 850 °C under a flowing Ar atmosphere. A circulartransmission line model (c-TLM) was employed to calculate the specific contact resistance, and current-voltage (I-V) data were measured with HP4155A. The Ni/Pt/Au contacts without the annealing process showed nearly rectifying characteristics. The ohmic contacts were formed on the samples annealed at 500 °C for 30 sec and the I-V data showed a linear behavior. The specific contact resistance was 2.1 × 10-2 Ωcm2. However with increasing the annealing temperature above 600 °C, ohmic contacts were again degraded. Auger electron spectroscopy (AES) depth profiles were used to investigate the interfacial reactions between the trilayer and GaN. AES results suggested that Pt plays a significant role in forming ohmic contact as an acceptor at the interface. Atomic force microscope (AFM) also showed that the samples with good ohmic contact have very smooth surface.

Characterization of the Al/RuO2 Interface Upon Thermal Annealing

1990 ◽  
Vol 181 ◽  
Author(s):  
Quat T. Vu ◽  
E. Kolawa ◽  
M-A. Nicolet
Keyword(s):  
Contact Resistance ◽  
Annealing Temperature ◽  
Electrical Measurement ◽  
Specific Contact Resistance ◽  
Annealing Duration ◽  
Type Model ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Specific Contact

ABSTRACTWe have characterized the Al/RuO2 interface after annealing at temperatures in the range 450° C-550° C for durations up to several hours by backscattering spectrometry, cross-sectional transmission electron microscopy, and electrical four point probe measurement of specially designed structures. The electrical measurement yields the specific contact resistance of the interface by applying a transmission line type model developped for this purpose. An interfacial aluminum-oxygen polycrystalline compound is shown to grow with annealing temperature and duration, with a concurrent reduction of a thin layer of RuO2. However, the specific contact resistance between Al and RuO2 is found to decrease with annealing duration at 500°C. This last result indicates that the interfacial reaction does not lead to an insulating interface as could have been expected if the growth were pure and dense A12O3.

scholarly journals Ti/Al Ohmic Contacts to n-Type GaN Nanowires

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Gangfeng Ye ◽  
Kelvin Shi ◽  
Robert Burke ◽  
Joan M. Redwing ◽  
Suzanne E. Mohney
Keyword(s):  
Thermal Stability ◽  
Contact Resistance ◽  
Cross Sections ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Transmission Line Model ◽  
Gan Nanowires ◽  
Transmission Electron ◽  
Titanium Aluminum ◽  
Specific Contact

Titanium/aluminum ohmic contacts to tapered n-type GaN nanowires with triangular cross-sections were studied. To extract the specific contact resistance, the commonly used transmission line model was adapted to the particular nanowire geometry. The most Al-rich composition of the contact provided a low specific contact resistance (mid10−8 Ωcm2) upon annealing at 600 °Cfor 15 s, but it exhibited poor thermal stability due to oxidation of excess elemental Al remaining after annealing, as revealed by transmission electron microscopy. On the other hand, less Al-rich contacts required higher annealing temperatures (850 or 900 °C) to reach a minimum specific contact resistance but exhibited better thermal stability. A spread in the specific contact resistance from contact to contact was tentatively attributed to the different facets that were contacted on the GaN nanowires with a triangular cross-section.

Fabrication and electrical characteristics of Ti/Al ohmic contact to Si+ implanted GaN

2005 ◽  
Vol 892 ◽  
Author(s):  
Nobuyuki Ito ◽  
Akira Suzuki ◽  
Mitsunori Kawamura ◽  
Kazuki Nomoto ◽  
Takeshi Kasai ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Smooth Surface ◽  
Surface Region ◽  
Specific Contact Resistance ◽  
Uniform Structure ◽  
Electrical Characteristics ◽  
High Impurity ◽  
Specific Contact ◽  
High Impurity Concentration

AbstractTi/Al ohmic contact with an extremely low specific contact resistance has been formed by the deposition of Ti and Al films on Si+ lanted GaN. The ohmic contact formed by annealing at 600 o C of Ti film with a thickness of 50 nm and Al film with a thickness of 200 nm reveals the good smooth surface and uniform structure as compare to those of contacts formed above 700 °C, which is correlated to whether the Al-Ti alloy is melted during the annealing of ohmic contact or not. The specific contact resistance of 2 × 10-6Ω-cm2 is obtained for Si+ implanted GaN with a dose of 5 × 1013 cm-2. As Si ion dose increases to 5 × 1014 /cm2, the specific contact resistance is reduced to 2 × 10-8 Ω-cm2. It is revealed that the selective doping at high impurity concentration in the surface region by Si+ implantation is useful to reduce the contact resistance for Ti/Al contact to GaN.

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.

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