TiN formed by ion beam nitriding of TiSi2

A low‐energy nitrogen ion beam has been used to transform part of a TiSi2 layer on Si to TiN. This process, in conjunction with a self‐aligned TiSi2 process, forms a self‐aligned TiN barrier layer. The nitriding was performed using a broad beam Kaufman ion source operated in N2 at 300‐eV beam energy. Various substrate temperatures and N2 ion doses were evaluated. Auger electron spectroscopy, cross‐sectional transmission electron microscopy, and etching in HF were used to characterize the samples. The results show that the nitrided surface layer grows in thickness with substrate temperature and exposure time to the ion beam, and that an equilibrium thickness can be reached. A comparison with films produced by conventional annealing in NH3 shows that superior film properties can be achieved by ion beam nitriding at temperatures below 500 °C.