Structural analysis of undoped microcrystalline silicon thin films deposited by PECVD technique

Undoped microcrystalline silicon thin films have been deposited by radio frequency powered plasma enhanced chemical vapour deposition technique. The structural order of silicon network in the films has been studied by Raman spectroscopy. The role of bonded hydrogen in the films and their consequences in microstructural defects have been obtained from the results of Fourier transform infrared spectroscopy. The presence of microcrystals and growth morphology of the microcrystalline films have been investigated by transmission and scanning electron microscopy, respectively. Optimized deposition conditions are obtained where properties of the microcrystalline films are suitable as absorber layer of solar cells. A highly conducting undoped microcrystalline film with 87% crystalline fraction (fc) is obtained, which exhibits columnar structure.