Epitaxial SrTiO3 (STO) films have been grown on TiN buffered Si(001) by pulsed laser deposition. The TSI layer was in situ deposited at 540, 640 or 720 degrees C whereas the STO film was grown at a fixed temperature of 640 degrees C. We have studied the effect of the growth temperature of TiN on the epitaxial relationship of STO/TiN heterostructures. It is found that for TiN grown at 540 or 640 degrees C the epitaxial relationship is (001)STO parallel to (001)TiN, and for TiN grown at 720 degrees C it changes to (101)STO parallel to (001)TiN and [(1) over bar 01]STO parallel to [1 (1) over bar 0]TIN (or [(1) over bar 01]STO parallel to [110]TiN). This change of relationship is accompanied by a sharp reduction in the out-of-plane lattice constant of the TiN layer. Fourier transform infrared spectra show that the longitudinal optic modes are active for all the STO films, but the absorption peak associated with the transverse optic mode is observed only in the (101) oriented STO films.