Low-ohmic contacts to α-SiC produced by laser technology methods

Developed in this paper are the method and technological scheme of forming of multilayer structures W/Si₃N₄/W/N to obtain ohmic contacts to α-SiC (N), by pulsed laser deposition (PLD) and laser annealing (LA). The optimal regimes for laser irradiation (PLI) were determined. When using Nd³⁺:YAG laser, laser annealing threshold levels of ohmic contacts based on SiC/W/Si₃N₄/W structures were determined. It is shown that the Q-switched regime with combined exposure of the fundamental (λ=1.06 μm) and double (λ=0.53 μm) harmonics is found to be optimal for obtaining minimal contact resistance when a YAG laser is used. It is shown that the threshold levels range of visual observed irreversible changes of resistivity with simultaneous voltage-current characteristic changes is found in area P _th=10⁷-2.8·10⁹ W/cm² in dependence from regimes of laser radiation and thickness of initial structures. Typical values of resistivity ρ₀ of elsewhere obtained ohmic contacts to α-SiC based on tungsten were close to the value ρ₁₁~5-6×10^-4 Ω·cm ²