3,4,9,10-Perylenetetracarboxylic dianhydride (PTCDA) was deposited on passivated Si(111) and GaAs(001) surfaces using organic molecular beam deposition (OMBD). The growth of the PTCDA films was monitored in situ and on-line by means of Raman spectroscopy. In addition, ex situ infrared (IR) spectra were recorded in order to observe the non-Raman active modes. Raman and IR spectra reveal molecular vibrational modes, allowing us to characterize the structural quality of the PTCDA films and the interaction with the substrate.