PROBING FOR FLUORINE IN NITRIDED SiO2 FILMS BY ION BEAM ANALYSIS

Particle induced γ-ray emission (PIGE) using the 19F(p, α γ)16O reaction and deuterium induced nuclear reaction analysis (NRA) were used to measure the uptake of fluorine in thin silicon oxide films which varied in thickness and had been nitrided under various conditions and annealing treatments. PIGE results show that 66 – 80 ppm of F was found in samples nitrided with F (as approximately 1% SiF4) in flowing nitrogen and heated at 1300°C for 1 hour. With NRA, it was not possible to measure these low concentrations because the background signal from silicon overlaps with the F signal. The increase of F in the nitrided specimens from 66 to 80 ppm follows an increase in film thickness from 3 to 53 nm indicating that F is incorporated in the film rather than being located at the surface of the specimen.