Fine-grained polysilicon films with built-in tensile strain

Abstract

Polysilicon (P-Si) refers to the structure of the silicon crystals as they are applied to the glass substrate. Polysilicon crystals are larger, more regularly shaped and more uniformly oriented in comparison with amorphous silicon (A-Si) and thus polysilicon is the most widely used structural material in current microdevices that are manufactured by surface micro machining. Polysilicon film usually show s a compressive built-in strain field. Strain diagnostic structures are used to elucidate that polysilicon films with built-in tensile strain can be achieved. We have reported that Boron doping is an indirect method for strain measurement and lattice spacing changes can be modeled by (Delta) a equals a0 X (ri - rs/rs X (Ni/Ns) where ri and r2 can be regarded as a radius of impurities and silicon atoms and Ni and Ns are the concentration of impurities and silicon.