Characterization of stress in doped and undoped polycrystalline silicon before and after annealing or oxidation with laser raman spectroscopy
Stress in polycrystalline silicon (poly-Si) was characterized with laser Raman spectroscopy. Effects of diffusion of phosphorus, annealing and oxidation on stress were especially studied. Relaxation of undirectional stress by annealing and oxidation was observed. Undirectional stress was relaxed by heavy doping of phosphorus which made a grain size larger. Compressive stress increased, however, by oxidation in poly-Si with a smaller grain size.