Using Rutherford backscattering spectrometry, nuclear reaction analysis, and elastic recoil detection analysis, we have analyzed the fluorine (F) and hydrogen (H) incorporated in thin tantalum pentoxide (Ta2O5) films on Si substrates prepared by plasma enhanced chemical vapor deposition using a tantalum pentafluoride (TaF5) source. It is shown that both F and H contents depend strongly on the deposition conditions, especially on the microwave power. Narrow resonant reaction F-19(alpha,p)Ne-22 analysis shows that there is considerable diffusion of F into the Si substrate.