DIFFUSION BARRIER STUDY ON TASIX AND TASIXNY

TaSi(x) and TaSi(x)N(y) films as diffusion barriers between aluminium and a silicon substrate have been investigated in this work. The grain sizes of the films were measured from transmission electron micrograp hs. The chemical binding was examined by X-ray photoelectron spectrosc opy. Then various sintering conditions were applied on Al/barrier/n+-p -Si diodes while the specific contact resistance and the diode reverse leakage current density were measured to study the stability of the T aSi(x) and TaSi(x)N(y) films as diffusion barriers. Results show that the TaSi(x)N(y) film can act as a better diffusion barrier than the Ta Si(x) film, even though the TaSi(x)N(y) film shows a slightly higher r esistivity (170 muOMEGA cm) than the TaSi(x) film (68 muOMEGA cm). The Al/TaSi(x)N(y)/n+-p-Si diode remained stable after sintering at 530-d egrees-C for 30 min, while the TaSi(x) film of the same thickness can no longer act as an effective barrier if the sintering temperature is higher than 475-degrees-C. The enhanced barrier property of the TaSi(x )N(y) film is caused by the additional existence of Si-N and Ta-N bond ings.