Photoluminescence of plasma enhanced chemical vapor deposition amorphous silicon oxide with silicon nanocrystals grown at different fluence ratios and substrate temperatures

Abstract

Near-infrared photolummescent dynamics of thermally annealed Si-rich SiOx, films grown by plasma enhanced chemical vapor deposition at different substrate temperatures and N2O/SiH4 fluence ratios are studied. The size of nanocrystallite Si (nc-Si) critically depends on the density of oxygen atoms in a Si-rich layer when the N2O/SiH4 ratio is smaller than 4; that is, it significantly increases at low N2O/SiH4 ratios. Deposition at a high N2O/SiH4 ratio strongly reduces the density of nc-Si and degrades the luminescence at 700-800 mn since the density of oxygen atoms is sufficient in the reaction of nc-Si with silicon atoms and formation of a stoichiometriC SiO2 matrix. Under a high RF power condition, the increasing substrate temperature usually inhibits the precipitation of nc-Si since high-temperature growth facilitates stochiometric SiO2 deposition. The disappearance of visible PL reveals the complete regrowth of a stoichiometric SiO2 matrix around a nanocrystallite Si cluster after annealing. The results of the transient luminescent analysis of Si-rich SiOx samples corroborate well with the observed values and reveal a lifetime of 43 mu s under an optimized nc-Si precipitation condition of 1100 degrees C annealing for 3 h.