Passivation Roles of Hydrogen Plasma Radicals on Crystallized Poly-Si

摘要

A post passivation method with H-plasma for crystallized poly-Si film was proposed and its mechanism was studied. Using H-plasma treatment will shorten the passivation time to 10-30 minutes instead of ten hours. In virtue of detecting the on-line optical emission spectroscopy (OES) during post Hplasma passivation and combined them with the measured Hall mobility, Raman spectra and absorption coefficient spectra the roles of H plasma radicals have been investigated. We have found that the intensity of different hydrogen plasma radicals along time for different crystallized poly-Si film material shows different actions during post H-plasma passivation. Radical Hαwith lower energy is mainly responsible for passivating the poly-Si crystallized by SPC which crystallization precursor was made by PECVD. Higher energy radicals H* may passivate the defects related to Ni impurity around the grain boundaries more effectively. In addition, the highest energy radicals Hβ and Hγ are needed to passivate intra-grain defects as in the poly-Si crystallized also by SPC but which precursor was made by LPCVD. It is strongly proofed that the Hplasma radicals and the passivation time needed for optimal passivation are related with the kind of crystallized poly-Si film material. At the end an optimization condition for each kind of crystallized poly-Si materials has been discussed.