Structural characterization of Ni and Ni/Ti ohmic contact on n-type 4H–SiC

Siad, M.; Abdesselam, M.; Souami, N.; Chami, A.C.

doi:10.1016/j.apsusc.2011.07.089

Cited by 10 publications

(4 citation statements)

References 22 publications

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“…Numerous metals and annealing procesess were used to study the ohmic characteristic on SiC substrates. Nickel is the most commonly used metal for n-type SiC and Al/Ti for p-type SiC [8], [9]. During annealing process (>1000˚C), nickel reacts with SiC substrates to form Ni silicides and result in a formation of graphite which deteriorate the electrical properties of the ohmic contact [10], [11].…”

Section: Introductionmentioning

confidence: 99%

Investigation on the ohmic characteristic of Ni/Ti/4H-SiC

et al. 2021

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Ohmic contact is important for silicon carbide (SiC) devices such as Schottky diode, junction field effect transistor (JFET) and metal oxide transistor (MOSFET). The effect of post metallization annealing (PMA) on the ohmic characteristics of Ni/Ti/4H-SiC is investigated. The samples were annealed under different ambients of high vacuum, forming gas and N2 gas at 1050˚C for 3 minutes using rapid thermal process (RTP). Current-voltage (I-V) measurements taken for different distances of a transmission line model (TLM) structure have been utilized to extract the contact resistivity. The correlation between surface roughness and resistivity has been investigated. It was found that the involvement of nitrogen during the annealing process at 1050˚C was ineffective to reduce the contact resistivity. The resistivity is improved when the samples were annealed in forming gas (FG), (a mixture of H2+N2) environment, showing that the incorporation of H2 gas during the annealing process has produced a better result. On the other hand, high vacuum PMA was found to be effective to improve the ohmic characteristic with higher current level at lower voltage. Hence, the enhanced performance observed in high vacuum annealing samples is beneficial to get ohmic contact on Ni/Ti/4H-SiC for PMA process with a low thermal budget.

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Section: Introductionmentioning

confidence: 99%

Investigation on the ohmic characteristic of Ni/Ti/4H-SiC

et al. 2021

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“…For the fabrication of ohmic contacts on n-type SiC, a nickel (Ni) or Ni-based alloy film is deposited on SiC and subsequently annealed at 1173 K or higher temperatures. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] At such high temperatures, Ni acts as a catalyst to break the strong bonds between Si and carbon (C) atoms in SiC, and various types of Ni-silicide are formed at the Ni=SiC interface through the reaction of Ni and Si atoms. Since this annealing is carried out nearly at the final stage of device fabrication processes, specially designed device structures are necessary to reduce the adverse effects of high temperature.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond-laser-induced modifications on a 4H-SiC surface and their application to low-temperature diffusion at the Ni/SiC interface

Okada

Tomita

Ueki

et al. 2018

Jpn. J. Appl. Phys.

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We carried out cross-sectional transmission electron microscopy to investigate the diffusion at the Ni/SiC interface enhanced by femtosecond-laser-induced modifications. The surface of a 4H-SiC crystal was irradiated with femtosecond laser pulses along lines, and a Ni film was then deposited. A thin modified layer was introduced by densely irradiating the SiC surface with line spacing close to the laser-beam diameter. After annealing, a layered structure was formed at the Ni/SiC interface, composed of a C layer sandwiched between the layers of Ni and Ni–Si alloy. The formation of Ni-silicide, i.e., Ni2Si and NiSi, was detected by micro-Raman spectroscopy. The distribution of C visualized by electron energy loss spectroscopy clearly shows that C atoms were released from the dissolved SiC and subsequently diffused through the Ni-silicide layer towards the Ni film surface.

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“…[14] One solution to improve the contact stability is to use bilayer metallization to consume the released carbon precipitate. [15] Ta is a well-known refractory metal with a high melting point and remarkable mechanical properties. It can also react with C to form tantalum carbides.…”

Section: Introductionmentioning

confidence: 99%