Amorphous Ta–Si–N diffusion barriers on GaAs

Abstract

Binary Ta–Si and ternary Ta–Si–N films of various compositions were deposited by reactive r.f. magnetron sputtering from Ta 5Si 3 target and tested as diffusion barriers between GaAs and Au. All as-deposited films were amorphous and conducting. Their resistivity and crystallisation temperature increased with increasing nitrogen. While nitrogen-free Ta–Si films crystallised at 600 °C, for the most stable Ta 34Si 25N 41 layers crystallisation occurred above 900 °C. 100 nm thick Ta 34Si 25N 41 films prevented interaction between Au and GaAs during annealing at temperatures up to 800 °C.