FOURIER-TRANSFORM INFRARED ATTENUATED TOTAL REFLECTION SPECTRA OF ION-IMPLANTED SILICA GLASSES

Fourier transform infrared attenuated total reflection spectra of silica glasses implanted with Si or P were measured using a Ge as an internal reflection element. Calculated penetration depth of the infrared radiation is 0.2-1.0-mu-m depending on the wavelength. These values are comparable to the depths of ions implanted at conventional acceleration voltages. Upon implantation the frequencies of omega-4 (LO) and omega-4 (TO) shifted to lower energy, whereas omega-3 moved to higher energy. This opposite direction of the frequency shift was explained by a decrease in the Si-O-Si bridging angle, which is caused by ion-bombarded compaction. The magnitude of frequency shifts observed were much larger than that in thermally compacted silica glasses reported so far, showing that an extremely high fictive temperature state is realized in the implanted silica glass layers.