Investigation of Ni/Ta contacts on 4H silicon carbide upon thermal annealing

• Published in: Applied surface science Vol. 254; no. 1; pp. 139 - 142
• Main Authors: Cao, Y., Pérez-García, S.A., Nyborg, L.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 31-10-2007; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Electrical properties of specific thin films; Electrical properties of specific thin films and layer structures (multilayers, superlattices, quantum wells, wires, and dots); Electron and ion emission by liquids and solids; impact phenomena; Electron impact: auger emission; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Impact phenomena (including electron spectra and sputtering); Interface structure and roughness; Interfacial reactions; Materials science; Metal contact; Methods of deposition of films and coatings; film growth and epitaxy; Nickel; Physics; Silicon carbide; Solid surfaces and solid-solid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Tantalum; Thin films; Thin films; Tantalum; Silicon carbide; 81.70.Jb; Metal contact; 82.80 Pv; Nickel; 81.15.cd; 81.05.Hd; Interfacial reactions; In situ; XRD; Amorphous state; Silicon carbide; Metal contact; Interfacial reactions; Nickel; Tantalum; Thin films; AES; Thickness; 81.05.Hd; 81.15.cd; 81.70.Jb; 82.80 Pv; Temperature effects; Transition elements; Ohmic contacts; Interface reaction; Thermal annealing; IV characteristic
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2007.07.007

Nickel and Tantalum thin films with 3:5 thickness ratios were deposited in succession onto 4H–SiC substrate at room temperature. The samples were then heated
in situ in vacuum at 650, 800 or 950
°C for 30
min. Glancing angle X-ray diffraction (XRD), Auger electron spectroscopy (AES) and current–voltage (
I–
V) technique were used for characterising the interfacial reactions and electrical properties. Amorphous Ni–Ta can be formed by solid-state reaction at 650
°C. The minor dissolved Ni in the Ta metal promotes the reaction between Ta and SiC. With increasing annealing temperature up to 950
°C, the dominant carbide changes from Ta
2C to TaC and a layer structure is developed. Electrical measurements show that ohmic contact is formed after annealing at or above 800
°C.