IMPROVED UNDERSTANDING OF THE SURFACE-PASSIVATING PROPERTIES OF RPECVD SILICON NITRIDE ON P-TYPE CRYSTALLINE SILICON

摘要

The outstanding surface passivation properties of remote plasma-enhanced chemical vapour deposited (RPECVD) silicon nitride (SiN_x) films developed at ISFH clearly correlate with Si/N-ratio. Since the physical reason of this correlation is still unknown, this work presents a comprehensive study of the relationship between film composition and surface passivation quality of RPECVD SiN_x on p-type crystalline silicon. The films were characterised by photoconductance decay measurements, infrared spectroscopy, nuclear reaction analysis and capacitance voltage curves recorded in the dark and ― for the first time ― under illumination using Al/SiN_x/p-Si metal-nitride-silicon capacitors. As a key result clear correlations were found between the surface recombination velocity and the concentration of N and Si dangling bonds in the volume of SiN_x films featuring a refractive index of 1.9 and 2.1, respectively.