The diffusion of As into p-type substrates, from As-implanted TiSi2 layers, was investigated for various heat treatments at temperatures of between 900 and 1100C. The drive-in diffusion was carried out by using either rapid thermal annealing or traditional furnace annealing. Shallow (20 to 80nm deep) junctions were obtained when there was a high (1019 to 1020/cm3) dopant concentration at the silicide/Si interface. The amount of diffused As, as measured using Rutherford back-scattering spectrometry, increased linearly with the square root of the annealing time. A similar relationship was found for the amount of electrically active As, as deduced from the use of Van der Pauw and anodic oxidation techniques. The 2 quantities were different, and the inactive dopants precipitated in the diffused layer, as revealed by transmission electron microscopy. It was suggested that this behavior was associated with the high tensile stress that was created by the silicide layer, and with its effect upon solid solubility and upon the clustering of As atoms. The precipitates were easily dissolved by annealing in the absence of a TiSi2 layer.

F.La Via, V.Privitera, S.Lombardo, C.Spinella, V.Raineri, E.Rimini, P.Baeri, G.Ferla: Journal of Applied Physics, 1991, 69[2], 726-31