Phosphorus out-diffusion during high temperature anneal of phosphorus doped polycrystalline silicon and SiO(2).

Loss of phosphorus by evaporation, from doped polysilicon and SiO2 films, due to high temperature anneals has been investigated by use of neutron activation analysis technique. It is found that large amount of phosphorus, as much as 99%, are lost from polysilicon films during inert ambient anneals. The loss is dependent on the temperature and time of anneal and on the initial phosphorus concentration. There is no loss in oxidizing ambients.