Diffusion data were presented for 98Mo implanted (180keV,  8.9 x 1013/cm2) into SiO2 layers that had been thermally grown on Si and annealed at 300 to 1000C. The Mo exhibited negligible diffusion: < 8 x 10-19cm2/s at 1000C. In general, the diffusivity in SiO2 was significantly smaller than that in Si.

Diffusion of 18 Elements Implanted into Thermally Grown SiO2. H.G.Francois-Saint-Cyr, F.A.Stevie, J.M.McKinley, K.Elshot, L.Chow, K.A.Richardson: Journal of Applied Physics, 2003, 94[12], 7433-9