Optimization of ICP-CVD silicon nitride for Si solar cell passivation

We have carried out a feasibility study on using inductively coupled plasma CVD (ICP-CVD) based SiN_x:H as an anti-reflective coating and for surface passivation of c-Si solar cells. It is seen that for certain range of gas flows the films showed blistering upon firing. Film deposition process was optimized to eliminate the blistering problem. Using extensive fourier transform infrared spectroscopy (FTIR) studies, it is shown that the blistering is due to release of hydrogen in the film and process optimization should target to achieve low hydrogen concentration. Optimized recipes with low interface state density and high positive charges were developed and surface recombination velocity of 1.9 cm/sec was obtained..