LPCVD RexSiyNz diffusion barriers in Si/SiO2/Cu metallizations

Low pressure chemical vapor deposition RexSiyNz thin films are investigated as diffusion barriers between Cu overlayers and oxidized silicon substrates. Gaseous precursors are silane, in situ fabricated rhenium chloride, ammonia, hydrogen and argon. Thermodynamic simulation of the Re-Si-N system is combined to the experimental study. The as-deposited RexSiyNz films are found to be amorphous or nanocrystalline. The 〈Si〉/SiO2/RexSiyNz(200 nm)/Cu(100 nm) metallizations are tested up to 1273 K by a 1 min RTP annealing in vacuum. The barrier performance is characterized with SEM, RBS and AES, for different RexSiyNz film composition and annealing temperature. RexSiyNz films properties are compared with MeSiN (where Me = Ta, W, Mo, Ti) films obtained by physical deposition methods.