Non-crystalline layers were studied with regard to their barrier effect upon O diffusion. It was found that the penetration depth of O diffusion decreased markedly with increasing Si content of a TaSiN layer, and reached 20nm in a Ta22Si35N43 layer. However, the resistivity also increased. A good diffusion barrier layer with a low sheet resistance was represented by Ta50Si16N34. Penetration depths of less than 40nm were observed in a slightly Si-rich Ta36Si27N37 layer during O2 annealing at 850C.

T.Hara, M.Tanaka, K.Sakiyama, S.Onishi, K.Ishihara, J.Kudo: Japanese Journal of Applied Physics - 2, 1997, 36[7B], L893-5