Microstructure and initial growth characteristics of the low temperature microcrystalline silicon films on silicon nitride surface

Microstructure and initial growth characteristics of the hydrogenated micro crystalline Si (muc-Si:H) films grown on hydrogenated amorphous silicon nit ride (a-SiNx:H) surface at low temperature were investigated using high res olution transmission electron microscope and micro-Raman spectroscopy. With increasing the Si and Si-H contents in the SiNx:H surfaces, muc-Si crystal lites, a few nanometers in size, were directly grown on amorphous nitride s urfaces. It is believed that the crystallites were grown through the nuclea tion and phase transition from amorphous to crystal in a hydrogen-rich ambi ent of gas phase and growing surface. The crystallite growth characteristic s on the dielectric surface were dependent on the stoichiometric (x=N/Si) r atio corresponding hydrogen bond configuration of the SiNx:H surface. Surfa ce facetting and anisotropic growth of the Si crystallites resulted from th e different growth rate on the different lattice planes of Si. No twins and stacking faults were observed in the (111) lattice planes of the Si crysta llites surrounding the a-Si matrix. This atomic-scale structure was conside red to be the characteristic of the low temperature crystallization of the muc-Si:H by the strain relaxation of crystallites in the a-Si:H matrix. (C) 2001 American Institute of Physics.