Effect of annealing temperature on the contact properties of Ni/V/4H-SiC structure

Abstract

A sandwich structure of Ni/V/4H-SiC was prepared and annealed at different temperatures from 650 °C to 1050 °C. The electrical properties and microstructures were characterized by transmission line method, X-ray diffraction, Raman spectroscopy and transmission electron microscopy. A low specific contact resistance of 3.3 × 10-5 Ω·cm2 was obtained when the Ni/V contact was annealed at 1050 °C for 2 min. It was found that the silicide changed from Ni3Si to Ni2Si with increasing annealing temperature, while the vanadium compounds appeared at 950 °C and their concentration increased at higher annealing temperature. A schematic diagram was proposed to explain the ohmic contact mechanism of Ni/V/4H-SiC structure.

High-temperature reliability of integrated circuit based on 4H-SiC MOSFET with Ni/Nb ohmic contacts for harsh environment applications

“…Many researchers have indicated that the operation lifetime of the SiC devices is strongly affected by the stability of the metal/SiC contact when operating in high temperature environment. 28,29) In general, Ni is known as a good candidate to form ohmic contact to n-type 4H-SiC because of low specific contact resistance. However, it has been reported that, during the annealing process at high temperature, Ni reacts with Si in the SiC substrate and forms Ni x Si y compounds.…”

CF4:O2 surface etching for the improvement of contact resistance and high-temperature reliability in Ni/Nb ohmic contacts on n-type 4H-SiC

“…[8][9][10][11] It has been reported that the operation lifetime of the SiC-based devices is not limited by the semiconductor properties itself, however, it is strongly governed by the reliability of the metal/SiC contacts. [12][13][14][15][16] A. V. Kuchuk et al reported that the Au/Ni 2 Si/n-SiC contact completely failed after 150 h of aging at 400 °C because of the interdiffusion/ reaction processes in the contact. 17) Therefore, fabrication ohmic contact with low specific contact resistivity and high temperature reliability is a critical issue that needs to be overcome to introduce SiC devices into reality.…”

Influence of Ni and Nb thickness on low specific contact resistance and high-temperature reliability of ohmic contacts to 4H-SiC

“…[7][8][9][10] However, much of the literature has indicated that reliable operation of SiC-based electronic devices is not limited by the electronic properties of the semiconductor itself but is strongly affected by the reliability and stability of the metal/SiC contacts. [11][12][13][14][15] For these reasons, fabrication of ohmic contacts to SiC with low specific contact resistivity and high-temperature stability is critical for applications in harsh environments.…”

“…This carbon agglomeration was reported to cause a higher surface roughness, increasing the contact resistance and the degradation of the devices when operating in a high-temperature environment. 13,[29][30][31][32] To solve this problem, a Ni-based multilayer with other metallic elements has been investigated. The added metal should have ability to react with the carbon and form a stable metal carbide.…”