Low-Resistance Ohmic Contact Formation by Laser Annealing of N-Implanted 4H-SiC

Abstract

In this work, pulsed-laser-based tempering was applied for post-implant annealing of n-type N-doped 4H-SiC in order to electrically activate the dopants and to rebuild the crystal structure. The annealing was performed by a frequency-tripled Nd:YVO4 laser with a pulse duration of 60 ns. To evaluate the effects of post-implant annealing, JBS diodes were electrically characterized. The results were compared with implanted, not post-annealed JBS diodes. The electrical measurements showed a significant on-state voltage drop of 40 mV at 6 A for post-implant laser annealed diodes compared to not post-implant annealed diodes.

Fabrication of Ohmic Contact on N-Type SiC by Laser Annealed Process: A Review

“…For an electrode material to form an Ohmic contact, it is closely related to the substrate material. A vast majority of the works reported were based on n-type 4H-SiC, as opposed to other substrates, such as 6H-SiC, semi-insulating 4H-SiC [13], and only Ni and Ti-based electrode materials have been reported [7,14,15]. Although different types of power device architectures can be fabricated to investigate the effect of laser annealing on the performance of ohmic contact, only simple device structures were used such as Schottky barrier diode and junction barrier Schottky diode [16,17].…”

Proven Power Cycling Reliability of Ohmic Annealing Free SiC Power Device through the Use of SmartSiC^TM Substrate

“…In the case of 4H-SiC substrate, we measured an expected sheet resistance mean value of 10.02 Ω/sq on 70 nm as-deposited NiAl2.6%. By annealing at different energies based on results from [4], we created homogenous ohmic contacts at energies of 2.4 J/cm² and above with a sheet resistance between 0.39 and 0.43 Ω/sq: see fig. 1a and 1b.…”