Backside Nickel Based Ohmic Contacts to n-Type Silicon Carbide

2008 ◽  
Vol 600-603 ◽  
pp. 635-638 ◽  
Author(s):  
Reza Ghandi ◽  
Hyung Seok Lee ◽  
Martin Domeij ◽  
Carl Mikael Zetterling ◽  
Mikael Östling
Keyword(s):  
Silicon Carbide ◽  
Ohmic Contacts ◽  
Annealing Temperature ◽  
Contact Resistivity ◽  
Optimum Conditions ◽  
Power Devices ◽  
High Quality ◽  
Temperature Range ◽  
Type Silicon ◽  
Different Temperatures

This work focuses on Ni ohmic contacts to the C-face (backside) of n-type 4H-SiC substrates. Low-resistive ohmic contacts to the wafer backside are important especially for vertical power devices. Ni contacts were deposited using E-beam evaporation and annealed at different temperatures (700-1050 °C) in RTP to obtain optimum conditions for forming low resistive ohmic contacts. Our results indicate that 1 min annealing at temperatures between 950 and 1000 °C provides high quality ohmic contacts with a contact resistivity of 2.3x10-5 Ωcm2. Also our XRD results show that different Ni silicide phases appear in this annealing temperature range.

scholarly journals Toward a Better Understanding of Ni-Based Ohmic Contacts on SiC

2011 ◽  
Vol 679-680 ◽  
pp. 465-468 ◽  
Author(s):  
Satoshi Tanimoto ◽  
Masanori Miyabe ◽  
Takamitsu Shiiyama ◽  
Tatsuhiro Suzuki ◽  
Hiroshi Yamaguchi ◽  
...  
Keyword(s):  
Thin Layer ◽  
Ohmic Contacts ◽  
Annealing Temperature ◽  
Contact Resistivity ◽  
Temperature Range ◽  
Carbon Vacancy ◽  
Substrate Interface ◽  
Plausible Model

There is still little consensus regarding why low contact resistivity is achieved when Ni on n-type 4H- and 6H-SiC is annealed at temperatures of more than above 950°C. The objective of this paper is to provide an answer concerning to this question. It is has been reported that even Ni-based contacts formed in the n++ region exhibited a steep reduction of contact resistivity in an annealing temperature range > 900°C. This effect reduction cannot be explained by the carbon vacancy induced donor model (Vc model) proposed by Han and his coworkers [Appl. Phys. Lett., Vol. 79, p. 1816 (2001)]. And, it is clarified that It was observed that the surface of substrates annealed at 1000°C was not covered with not Ni2Si but with a thin layer of NiSi. Finally, a plausible model is proposed that as the result of annealing at higher temperatures, results in the formation of the a NiSi/SiC system is builtat the substrate interface, resulting in significant reduction in low causing contact resistivity to be reduced significantly.

scholarly journals Ohmic contacts to Si-implanted and un-implanted n-type GaN

1995 ◽  
Vol 395 ◽  
Author(s):  
J. Brown ◽  
J Ramer ◽  
K. ZHeng ◽  
L.F. Lester ◽  
S.D. Hersee ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Annealing Temperature ◽  
Contact Resistivity ◽  
Contact Structures ◽  
Specific Contact Resistance ◽  
Resistance Variation ◽  
Specific Contact ◽  
Metal Layers ◽  
Nitrogen Vacancies

ABSTRACTWe report on ohmic contacts to Si-implanted and un-implanted n-type GaN on sapphire. A ring shaped contact design avoids the need to isolate the contact structures by additional implantation or etching. Metal layers of Al and Ti/Al were investigated. On un-implanted GaN, post metalization annealing was performed in an RTA for 30 seconds in N2 at temperatures of 700, 800, and 900°C, A minimum specific contact resistance (rc) of 1.4×10−5 Ω-cm2 was measured for Ti/Al at an annealing temperature of 800°C. Although these values are reasonably low, variations of 95% in specific contact resistance were measured within a 500 µm distance on the wafer. These results are most likely caused by the presence of compensating hydrogen. Specific contact resistance variation was reduced from 95% to 10% by annealing at 900°C prior to metalization. On Si-implanted GaN, un-annealed ohmic contacts were formed with Ti/Al metalization. The implant activation anneal of 1120°C generates nitrogen vacancies that leave the surface heavily n-type, which makes un-annealed ohmic contacts with low contact resistivity possible.

Thermal Stability of Ti/Pt/Au Non-Alloyed Ohmic Contacts on InN

1994 ◽  
Vol 337 ◽  
Author(s):  
F. Ren ◽  
C. R. Abernathy ◽  
S. J. Pearton ◽  
P. W. Wisk
Keyword(s):  
Thermal Stability ◽  
Doping Level ◽  
Room Temperature ◽  
Ohmic Contacts ◽  
Contact Resistivity ◽  
High Doping Level ◽  
Transmission Line Method ◽  
Different Temperatures ◽  
Contact Resistivities ◽  
Thermal Stability Of

ABSTRACTExtremely low contact resistance of non-alloyed Ti/Pt/Au metallization on n-type InN is demonstrated. The contacts were annealed at different temperatures up to 420 °C to investigate their thermal stability. A low contact resistivity of 1.8 x 10-7 ohm-cm2 was measured at room temperature using the transmission line method. This was due to the extremely high doping level (5 x 1020 cm-3) in the InN. After 300 °C annealing, the contact resistivity increased to 2.4 x 10-7 ohm-cm2- For 360 °C annealing, the contact morphology showed some degradation, but the contact resistivity was almost the same as at 300 °C. There was serious degradation of the contacts after 420 °C annealing. The morphology became very rough, and the contact and sheet resistances increased by factors of 3-5 times. This degradation is believed due to the decomposition of the InN film. The contact resistivities between n-type epitaxial GaAs and InN were also investigated, and showed values around 10-4 ohm-cm2.

Analysis of the Gas Phase Epitaxy of Silicon Carbide as a Basic Process for Power Elec-tronics Technology. Review

2020 ◽  
Vol 25 (6) ◽  
pp. 483-396
Author(s):  
A.V. Afanasev ◽  
◽  
V.A. Ilyin ◽  
V.V. Luchinin ◽  
S.A. Reshanov ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Gas Phase ◽  
Epitaxial Layers ◽  
Power Devices ◽  
High Quality ◽  
Main Method ◽  
Technological Factors ◽  
Current State ◽  
Individual Task ◽  
Technology Review

Currently, chemical gas deposition is the main method for producing high-quality and reproducible epitaxial layers for commercial silicon carbide (SiC) power devices. Based on the experience of ETU «LETI» in the synthesis of monocrystalline SiC, an analysis of the current state of silicon carbide gas phase epitaxy (CVD) technology was carried out. It has been shown that modern CVD reactors allow to implement the growth processes of SiC epitaxial structures of high quality with the following parameters: substrates diameter up to 200 mm; thicknesses of epitaxial layers from 0.1 to 250 μm; layers of n - and p -types conductivity with ranges of doping levels 10-10 cm and 10-10 cm, respectively. At the same time, setting up the technology of the reproducible high-quality growth of epitaxial layers is an individual task for a specific type of reactor. It requires a detailed consideration of the technological factors presented in this paper, which at the end determine the achievable parameters of SiC-epitaxial products

Effects of Si interlayer conditions on platinum ohmic contacts for p-type silicon carbide

2002 ◽  
Vol 31 (5) ◽  
pp. 506-511 ◽  
Author(s):  
T. Jang ◽  
J. W. Erickson ◽  
L. M. Porter
Keyword(s):  
Silicon Carbide ◽  
Ohmic Contacts ◽  
Type Silicon ◽  
P Type

Formation and role of graphite and nickel silicide in nickel based ohmic contacts to n-type silicon carbide

2005 ◽  
Vol 97 (8) ◽  
pp. 083709 ◽  
Author(s):  
I. P. Nikitina ◽  
K. V. Vassilevski ◽  
N. G. Wright ◽  
A. B. Horsfall ◽  
A. G. O’Neill ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Ohmic Contacts ◽  
Nickel Silicide ◽  
Type Silicon
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