INTERFACIAL REACTION AND SILICIDE FORMATION IN PD A-SI-H LAYERED FILMS/

In this study, a layered film composed of Pd and hydrogenated amorphou s silicon (a-Si:H) is thermally annealed at a constant heating rate, a nd the interfacial reaction as well as the formation mechanism of the Pd silicide (Pd2Si) are investigated by techniques such as hydrogen ev olution, analysis, X-ray diffraction, and Rutherford backscattering sp ectrometry. The silicide formation reaction at the interface of Pd/a-S i:H is activated from approx. 250 degrees C. It is seen that Pd silici de in the amorphous state is generated at the initial stage of the rea ction, which is gradually crystallized to grow to stable Pd2Si. Hydrog en is released in this silicide formation reaction, and the Pd2Si form ation process is exactly reflected on the hydrogen evolution spectrum. As to the growth of Pd2Si, the following conjecture is made. The grow th rate of Pd2Si is controlled by the interfacial reaction of Pd/a-Si: H at the initial stage where the Pd2Si layer is thin and by the diffus ion of Pd in Pd2Si when the Pd2Si layer becomes thick. Based on these results, the Pd2Si formation model is proposed. Using the model, the r eaction rate constant between pd and a-Si:H, the diffusion constant of Pd in Pd2Si, and the growth rate of Pd2Si are investigated. The resul ts of measurement agreed well with the results of previous reports, an d demonstrated the validity of the model. (C) 1997 Scripta Technica, I nc.