Schottky–ohmic transition in nickel silicide/SiC-4H system: is it really a solved problem?

Application of angle‐resolved XPS for characterisation of SiC/Ni2Si thin film systems

“…3,4 Among the different SiC polytypes, the 4H-SiC is of major interest due to its higher electron mobility and wider band gap compared with other polytypes. 5 Nickel has been used extensively as the transition metal for the formation of the contact with SiC because of its ability to form stable silicides yielding low contact resistivity.…”

“…4,6,7 Different silicides may form as a result of Ni/SiC reaction above 400°C, but the dominant species, Ni 2 Si, is reported to have an ohmic behaviour after heat treatment at above 900°C. 3,4 This behaviour is supposed to be related to the graphite formation on the Ni 2 Si surface, leading to vacancies and electron donors due to tunnelling processes that contribute to the Ni 2 Si/SiC contact properties. 3,4,7 The surface and interface chemistry of the SiC/Ni-silicide system by means of angle-resolved X-ray photoelectron spectroscopy (ARXPS) were studied for both core level and valence band spectra.…”

“…3,4 This behaviour is supposed to be related to the graphite formation on the Ni 2 Si surface, leading to vacancies and electron donors due to tunnelling processes that contribute to the Ni 2 Si/SiC contact properties. 3,4,7 The surface and interface chemistry of the SiC/Ni-silicide system by means of angle-resolved X-ray photoelectron spectroscopy (ARXPS) were studied for both core level and valence band spectra. In this study, dedicated samples were prepared by the sputtering of ultrathin homogeneous Ni layers on SiC single crystal and by their subsequent controlled heat treatment.…”

60–700 K CTAT and PTAT Temperature Sensors with 4H-SiC Schottky Diodes

“…La Via et al [ 50 ] report that a reaction between Ni and Si gives only the formation of the Ni 2 Si phase over a large annealing temperature range, between 600 °C and 950 °C. Later, the existence of a combination between Ni 31 Si 12 and Ni 2 Si phases at 600 °C with an increase in Ni 2 Si percentage at 950 °C was also observed by XRD [ 51 ]. Kuchuk et al [ 52 ] reported the formation of the Ni 2 Si phase as a result of a thermal treatment at 600 °C for 15 min.…”

Low-temperature diffusion assisted by femtosecond laser-induced modifications at Ni/SiC interface

“…One such problem is the difficulty of forming ohmic contacts on SiC. For contact formation on an n-type SiC, a Ni-based metallic film is deposited, followed by high-temperature annealing, typically above 1,223 K. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Because this contactformation process is conducted nearly at the final stage of device fabrication, specially designed device structures are necessary to reduce the adverse effect of the high annealing temperatures. Under such high temperatures, Ni serves as a catalyst to dissolve the strong atomic bonding between Si and C atoms and reacts with Si to form several types of Ni silicide.…”