Correlation between microstructure and properties of hydrogenated Si thin films grown by plasma enhanced chemical vapor deposition under different hydrogen flow rates

In order to characterize the surface of nanocrystalline hydrogenated silicon (nc-Si:H) and to get more insight into the film's growth deposited by plasma enhanced chemical vapor deposition (PECVD), spectroscopic ellipsometry measurements have been performed after deposition of profiled layers at different hydrogen flow rate (FH2). This study showed that by increasing the FH2, the layer's thickness decrease and at the same time the Tauc's optical band gap remains as high as 1.45 eV or much higher. This can be attributed to either the presence of microvoids in the films or an increase in the bonded hydrogen content.