Investigation on optical and electrical properties of LPCVD SiO_xN_y thin films

Amorphous silicon oxynitride (a-SiO_xN_y) films of various compositions were deposited by low-pressure chemical vapour deposition (LPCVD) at temperature range of 820-880°C and 400 mTorr, using mixture of SiCl₂H₂-NH₃N ₂O. The investigation on optical and electrical properties was made using spectroellipsometry (SE) and the analyses of 1 MHz capacitance-voltage characteristics. To calculate optical and microstructural parameters of the films we used different approaches (Bruggeman-EMA, Cauchy, Sellmeier and Wemple-Di Domenico). The observed low densities of the interface traps are attributed to the nitrogen incorporation at the SiO_xN_y/Si interface which leads to suppression of their generation