Evolution of the Electrical and Structural Properties of Ti/Al/W Contacts to p-Type Implanted 4H-SiC upon Thermal Annealing

2015 ◽  
Vol 821-823 ◽  
pp. 428-431
Author(s):  
Marilena Vivona ◽  
Giuseppe Greco ◽  
Raffaella Lo Nigro ◽  
Salvatore di Franco ◽  
Filippo Giannazzo ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Melting Temperature ◽  
Thermal Annealing ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Good Choice ◽  
Specific Nature ◽  
Ohmic Behavior ◽  
Layer Contact ◽  
P Type

The mechanism of Ohmic contacts formation to p-type SiC is a fundamental and technological concern continuously under debate. Typically, Ti/Al-based contacts are a good choice for Ohmic contacts to p-type SiC, even though some aspects strictly related to the specific nature of Al (susceptibility to oxidation, low melting temperature, etc.) remain to be optimized. In this work, the evolution of the electrical properties of a Ti/Al/W multiple-layer contact has been studied by TLM characterization and correlated to the changes in the morphology and microstructure upon thermal annealing. The formation of an Ohmic contact has been observed after a thermal annealing at 1100°C, discussing the possible reasons determining the transition to an Ohmic behavior.

The Microstructure and Electrical Properties of Directly Deposited TiN Ohmic Contacts to Gallium Nitride.

1999 ◽  
Vol 595 ◽  
Author(s):  
P. Ruterana ◽  
G. Nouet ◽  
Th. Kehagias ◽  
Ph. Komninou ◽  
Th. Karakostas ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Electrical Properties ◽  
Film Thickness ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Epitaxial Relationship ◽  
Si Doped ◽  
P Type ◽  
20 Nm

AbstractWhen the stoichiometric TiN was deposited directly on GaN, we obtained columnar TiN grains of 5-20 nm section which cross the whole film thickness and are rotated mostly around the [111] axis. The conventional epitaxial relationship is obtained and no amorphous patches are observed at the interface. The deposition of TiN on Si doped GaN layers lead to the formation of an ohmic contact, whereas we obtain a rectifying contact on p type layers.

scholarly journals The microstructure and electrical properties of directly deposited TiN ohmic contacts to Gallium Nitride.

2000 ◽  
Vol 5 (S1) ◽  
pp. 887-893
Author(s):  
P. Ruterana ◽  
G. Nouet ◽  
Th. Kehagias ◽  
Ph. Komninou ◽  
Th. Karakostas ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Electrical Properties ◽  
Film Thickness ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Epitaxial Relationship ◽  
Si Doped ◽  
P Type ◽  
20 Nm

When the stoichiometric TiN was deposited directly on GaN, we obtained columnar TiN grains of 5-20 nm section which cross the whole film thickness and are rotated mostly around the [111] axis. The conventional epitaxial relationship is obtained and no amorphous patches are observed at the interface. The deposition of TiN on Si doped GaN layers lead to the formation of an ohmic contact, whereas we obtain a rectifying contact on p type layers.

scholarly journals Thermally Stable Ohmic Contact to p-Type 4H-SiC Based on Ti3SiC2 Phase

2016 ◽  
Vol 858 ◽  
pp. 553-556 ◽  
Author(s):  
Tony Abi-Tannous ◽  
Maher Soueidan ◽  
Gabriel Ferro ◽  
Mihai Lazar ◽  
Christophe Raynaud ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Magnetron Sputtering ◽  
Ohmic Contact ◽  
Room Temperature ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Specific Contact ◽  
Thermionic Field Emission ◽  
P Type

In this study, the electrical properties of Ti3SiC2 based ohmic contacts formed on p-type 4H-SiC(0001) 4°-off substrates were studied. The Ti3SiC2 thin films were grown by thermal annealing (from 900°C to 1200°C) of Ti50Al50 layer deposited by magnetron sputtering. XRD analyzes were performed on the samples to further investigate the compounds formed after annealing. Using TLM structures, the Specific Contact Resistance (SCR) at room temperature of all contacts was measured. The temperature dependence (up to 600°C) of the SCR was studied to understand the current mechanisms at the interface and to determine the barrier height value by fitting the experimental results using the thermionic field emission theory. Aging tests showed that Ti3SiC2 based contacts were stable up to 200h at 600°C under Ar.

Correlation between the electrical properties and the interfacial microstructures of TiAl-based ohmic contacts to p-type 4H-SiC

2004 ◽  
Vol 33 (5) ◽  
pp. 460-466 ◽  
Author(s):  
S. Tsukimoto ◽  
K. Nitta ◽  
T. Sakai ◽  
M. Moriyama ◽  
Masanori Murakami
Keyword(s):  
Electrical Properties ◽  
Ohmic Contacts ◽  
P Type

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.

Comparison between Ni-SALICIDE and Self-Aligned Lift-Off Used in Fabrication of Ohmic Contacts for SiC Power MOSFET

2019 ◽  
Vol 963 ◽  
pp. 490-493
Author(s):  
Tomasz Sledziewski ◽  
Tobias Erlbacher ◽  
Anton Bauer ◽  
Lothar Frey ◽  
Xi Ming Chen ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Silicon Dioxide ◽  
Ohmic Contacts ◽  
Positive Impact ◽  
Specific Resistance ◽  
Power Mosfet ◽  
Interlayer Dielectric ◽  
Lift Off ◽  
P Type

A comparison between self-aligned process (using lift-off) and Ni-SALICIDE used in fabrication of ohmic contacts for SiC Power MOSFET is done. Both processes are demonstrated for 3.3 kV SiC VDMOS transistors fabricated on 100 mm substrates. It is shown that the Ni-SALICIDE process with first silicidation at 500 °C does not degrade the electrical properties of silicon dioxide; particularly, a degradation of the interlayer dielectric between source and gate is not evident. Additionally, this first silicidation is found to have a positive impact on the specific resistance of contacts formed on p-type SiC using NiAl2.6% as an ohmic metal.

An Approach to Improving the Morphology and Reliability of n-SiC Ohmic Contacts to SiC Using Second-Metal Contacts

2006 ◽  
Vol 527-529 ◽  
pp. 859-862 ◽  
Author(s):  
Matthew H. Ervin ◽  
Kenneth A. Jones ◽  
Un Chul Lee ◽  
Taniya Das ◽  
M.C. Wood
Keyword(s):  
Electrical Properties ◽  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Chemical Properties ◽  
Physical Contact ◽  
Metal Contacts ◽  
Critical Feature ◽  
Excess Carbon ◽  
Ohmic Contact Formation

While nickel ohmic contacts to n-type silicon carbide have good electrical properties, the physical contact, and therefore the reliability, can be poor. An approach is described for using the good electrical properties of Ni ohmic contacts while using another metal for its desired mechanical, thermal and/or chemical properties. In the present work, once the Ni contacts have been annealed forming nickel silicides and achieving low contact resistance, they are etched off. Removing the primary Ni contacts also eliminates the poor morphology, voids, and at least some of the excess carbon produced by the Ni/SiC reaction. The Ni contacts are then replaced by a second contact metal. This second metal displays low contact resistance as-deposited, indicating that the critical feature responsible for the ohmic contact has not been removed by the primary contact etch. Not only does this approach provide more flexibility for optimizing the contact for a given application, it also provides some insight into the ohmic contact formation mechanism.

The Development of Solid Phase Regrowth on GaAs and its applications

1993 ◽  
Vol 319 ◽  
Author(s):  
L. C. Wang
Keyword(s):  
Ohmic Contacts ◽  
Solid Phase ◽  
Low Loss ◽  
Ohmic Behavior ◽  
Gaas Substrates ◽  
Layer Structures ◽  
Solid Phase Reactions ◽  
Solid Phase Regrowth ◽  
P Type ◽  
Ohmic Contact Formation

AbstractA solid phase regrowth process on GaAs has been observed in Pd- and Ni- based bi-layer structures, e.g. the Si/Ni, the Ge/Pd, the In/Pd, and the Sb/Pd structures. Due to the regrowth, uniform epitaxial layers of Ge, GaAs, InxGa1-xAs, and GaSbl-xAsx on GaAs substrates by solid phase reactions can achieved. The model of this regrowth process will be presented. Based on this regrowth mechanism, a series of non-spiking planar ohmic contacts on n and p type GaAs have been developed. Low contact resistivity in the range of mid 10−7 Ω-cm2 was obtained. The ohmic contact formation mechanism of these contacts will also be discussed. All the studies suggest that the ohmic behavior is a result of the formation of an n+ or p+ surface layer via solid phase reactions. The regrowth process has also been utilized to achieve compositional disordering of GaAs/AlGaAs superlattices, and low loss AlGaAs/GaAs waveguide has been obtained.

Ohmic Contact Formation to Doped GaN

1995 ◽  
Vol 395 ◽  
Author(s):  
L. L. Smith ◽  
M. D. Bremser ◽  
E. P. Carlson ◽  
T. W. Weeks ◽  
Y. Huang ◽  
...  
Keyword(s):  
Ohmic Contact ◽  
Electron Beam Evaporation ◽  
Integrated Analysis ◽  
Cross Sectional ◽  
Contact Materials ◽  
Ohmic Behavior ◽  
Specific Contact ◽  
P Type ◽  
Ohmic Contact Formation ◽  
Contact Resistivities

ABSTRACTOhmic contact strategies for n- and p-type GaN have been investigated electrically, chemically, and microstructurally using transmission line measurements, high-resolution EELS and cross-sectional TEM, respectively. The contributions to contact performance from work function differences, carrier concentrations, annealing treatments, and interface metallurgy have been examined. The contact materials of Ti, TiN, Au, and Au/Mg were deposited via electron beam evaporation; Al was deposited via thermal evaporation. As-deposited Al and TiN contacts to highly doped n-GaN were ohmic, with room-temperature specific contact resistivities of 8.6×10−5 Ω cm2 and 2.5×10−5 Ωcm2 respectively. The Ti contacts developed low-resistivity ohmic behavior as a result of annealing; TiN contacts also improved with further heat treatment. For p-GaN, Au became ohmic with annealing, while Au/Mg contacts were ohmic in the as-deposited condition. The performance, structure, and composition of different contact schemes varied widely from system to system. An integrated analysis of the results of this study is presented below and coupled with a discussion of the most appropriate contact systems for both n- and p-type GaN.

Effects of Different Post-Implantation Annealing Conditions on the Electrical Properties of Interfaces to p-Type Implanted 4H-SiC

2012 ◽  
Vol 717-720 ◽  
pp. 825-828
Author(s):  
Alessia Frazzetto ◽  
Fabrizio Roccaforte ◽  
Filippo Giannazzo ◽  
R. Lo Nigro ◽  
M. Saggio ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Electrical Parameters ◽  
Capping Layer ◽  
Annealing Conditions ◽  
Specific Contact ◽  
Activation Annealing ◽  
P Type ◽  
Post Implantation

This paper reports on the effects of different post-implantation annealings on the electrical properties of interfaces to p-type implanted 4H-SiC. The morphology of p-type implanted 4H-SiC was controlled using a capping layer during post-implantation activation annealing of the dopant. Indeed, the surface roughness of Al-implanted regions strongly depends on the use of the protective capping layer during the annealing. However, while the different morphological conditions do not affect the macroscopical electrical properties of the implanted SiC (such as the sheet resistance), they led to an improvement of the morphology and of the specific contact resistance of Ti/Al Ohmic contacts formed on the implanted regions. These electrical and morphologic improvements were associated with a lowering of Schottky barrier height. Preliminary results showed that the different activation annealing conditions of p-type implanted SiC can affect also the electrical parameters (like threshold voltage and mobility) of lateral MOSFETs.

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