Development of an Extreme High Temperature n-Type Ohmic Contact to Silicon Carbide

Evans, Laura J.; Okojie, Robert S.; Lukco, Dorothy

doi:10.4028/www.scientific.net/msf.717-720.841

Cited by 6 publications

(5 citation statements)

References 7 publications

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“…A high thermal stability was observed for W-Ni ohmic contacts to n-type 4H-SiC characterized by specific contact resistivity of 7.69 × 10 −4 and 5.81 × 10 −4 cm 2 for doping level equal 1.4 and 2 × 10 19 cm −3 , respectively [22]. Similar value of specific contact resistivity equal 5 × 10 −4 cm 2 was obtained for W-Ni ohmic contact to n-type epitaxial layer with doping concentration in the range 5-7 × 10 18 cm −3 deposited on p-type 4H-SiC substrate [23].…”

Section: Introductionmentioning

confidence: 54%

Effects of annealing temperature on the structure and electrical properties of tungsten contacts to n-type silicon carbide

Rogowski

Kubiak

2015

Materials Science and Engineering: B

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Section: Introductionmentioning

confidence: 54%

Effects of annealing temperature on the structure and electrical properties of tungsten contacts to n-type silicon carbide

Rogowski

Kubiak

2015

Materials Science and Engineering: B

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“…After annealing at 1100 °C and above, W-rich structures corresponding to WC can be seen on Ni-rich fields corresponding to W x Ni y C with dissolved Si-all above Ni-Si-C regions that might be amorphous alloys or a poorly crystallized nickel silicide plus graphite. Previous work on W:Ni contacts [18,30] is now complemented with ρ c measurements for Ohmic contacts to p-4H-SiC along with further materials characterization to reveal the phase transformations and contact morphology. Ohmic contacts to p-SiC form with the W x Ni y C next to the SiC interface, but ρ c dropped slightly in some samples as Ni-Si-C regions came in contact with the SiC.…”

Section: Discussionmentioning

confidence: 99%

“…While XRD was primarily carried out on blanket thin films on p-SiC, a few samples on n-SiC support the formation of the W x Ni y C phase at 1100 °C and 1150 °C, as well as WC at 1150 °C. The presence of carbides would suggest the presence of a phase bearing silicon to complete the mass balance [18,30]. The XRD plots in figures 2-4 do not show any intense unidentified peaks, suggesting that a silicide phase may be amorphous or poorly crystallized.…”

Section: X-ray Diffractionmentioning

confidence: 97%

“…Other Ohmic contact research combined Ni and W layers with Ti [22,24] or Cr [22,25] on n-SiC; and Al [23,26,27] alone or along with Ti for p-SiC [28,29]. In addition to the aforementioned simultaneous study [18], a different W:Ni composition reported as 75 at.% W was Ohmic through 15 h of aging at 1000 °C on n-4H-SiC and n-6H-SiC (N D ≈5-7×10 18 cm −3 ) with ρ c ≈5×10 −4 Ω cm 2 [30]. In our paper, W:Ni thin films on both p-and n-4H-SiC display simultaneous Ohmic contact behavior with commensurate electrical values.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of tungsten–nickel simultaneous Ohmic contacts to p- and n-type 4H-SiC

Kragh-Buetow¹,

Okojie²,

Lukco³

et al. 2015

Semicond. Sci. Technol.

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Ohmic contacts to p-and n-type 4H-SiC using refractory alloyed W:Ni thin films were investigated. Transfer length measurement test structures to p-type 4H-SiC (N A =3×10 20 cm −3 ) revealed Ohmic contacts with specific contact resistances, ρ c , of ∼10 −5 Ω cm 2 after 0.5 h annealing in argon at temperatures of 1000 °C, 1100 °C, 1150 °C, and 1200 °C. Contacts fabricated on n-type 4H-SiC (N D =2×10 19 cm −3 ) by similar methods were shown to have similar specific contact resistance values after annealing, demonstrating simultaneous Ohmic contact formation for W:Ni alloys on 4H-SiC. The lowest ρ c values were (7.3±0.9)×10 −6 Ω cm 2 for p-SiC and (6.8±3.1)×10 −6 Ω cm 2 for n-SiC after annealing at 1150 °C. X-ray diffraction shows a cubic tungsten-nickel-carbide phase in the Ohmic contacts after annealing as well as WC after higher temperatures. Auger electron spectroscopy depth profiles support the presence of metal carbide regions above a nickel and silicon-rich region near the interface. X-ray energy dispersive spectroscopy mapping showed tungsten-rich and nickelrich regions after annealing at 1100 °C and above. W:Ni alloys show promise as simultaneous Ohmic contacts to p-and n-SiC, offering low and comparable ρ c values along with the formation of W x Ni y C.

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“…Other electronics technologies such as silicon on insulator (SOI) circuits have been known to operate in temperatures up to 300 o C 7 . Wide band gap electronics such as silicon carbide (SiC) have been demonstrated to operate in temperatures of 500 o C or more 8,9,10,11,12 . In all cases, there is an inverse relationship between temperature and electronics reliability.…”

mentioning

confidence: 99%

Approximation of Engine Casing Temperature Constraints for Casing Mounted Electronics

Kratz

Culley²,

Chapman³

2016

52nd AIAA/SAE/ASEE Joint Propulsion Conference

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The performance of propulsion engine systems is sensitive to weight and volume considerations. This can severely constrain the configuration and complexity of the control system hardware. Distributed Engine Control technology is a response to these concerns by providing more flexibility in designing the control system, and by extension, more functionality leading to higher performing engine systems. Consequently, there can be a weight benefit to mounting modular electronic hardware on the engine core casing in a high temperature environment. This paper attempts to quantify the in-flight temperature constraints for engine casing mounted electronics. In addition, an attempt is made at studying heat soak back effects. The Commercial Modular Aero Propulsion System Simulation 40k (C-MAPSS40k) software is leveraged with real flight data as the inputs to the simulation. A two-dimensional (2-D) heat transfer model is integrated with the engine simulation to approximate the temperature along the length of the engine casing. This modification to the existing C-MAPSS40k software will provide tools and methodologies to develop a better understanding of the requirements for the embedded electronics hardware in future engine systems. Results of the simulations are presented and their implications on temperature constraints for engine casing mounted electronics is discussed. F American Institute of Aeronautics and Astronautics 3 technology are high temperature electronics embedded on the engine core that allow transducer elements to act as intelligent modular devices with digital data interfaces (smart nodes). More information about the concept of DEC technology is provided in Ref. 1.In the near term, DEC technology provides aerodynamic and thermodynamic engine system benefits, but it also improves engine life cycle cost and can reduce the total system weight 1 . For example, DEC hardware can be more easily located or configured to reduce engine drag by shrinking the size of the FADEC mounted to the fan casing; high temperature electronics can improve heat quality for more efficient cooling while they are also located more easily on the engine; and reusable modular components can reduce design and manufacturing costs. In the long term, assuming the continued advancements in electronics, tremendous new control-based capabilities will be introduced that make significant contributions to engine performance, efficiency, and safety. For example, embedded signal processing can extract new information from each existing sensor location while more rapid control design can improve the accuracy and capabilities of the supervisory system control. Additional benefits to the DEC approach are discussed in Refs. 1, 2, 3, 4, and 5.The temperature environment on the engine will always be a concern even with high temperature electronics capability for embedded devices. For example, the state of the art materials technology for internal gas path components in the engine is approaching 1500 o C 6 , however, no known electronics technology can reli...

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Development of an Extreme High Temperature n-Type Ohmic Contact to Silicon Carbide

Cited by 6 publications

References 7 publications

Effects of annealing temperature on the structure and electrical properties of tungsten contacts to n-type silicon carbide

Effects of annealing temperature on the structure and electrical properties of tungsten contacts to n-type silicon carbide

Characterization of tungsten–nickel simultaneous Ohmic contacts to p- and n-type 4H-SiC

Approximation of Engine Casing Temperature Constraints for Casing Mounted Electronics

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