Effect of PECVD SiN_x/SiO_yN_x–Si interface property on surface passivation of silicon wafer简

It is studied in this paper that the electrical characteristics of the interface between Si Oy Nx/Si Nx stack and silicon wafer affect silicon surface passivation. The effects of precursor flow ratio and deposition temperature of the Si Oy Nx layer on interface parameters, such as interface state density Ditand fixed charge Qf, and the surface passivation quality of silicon are observed. Capacitance–voltage measurements reveal that inserting a thin Si Oy Nx layer between the Si Nx and the silicon wafer can suppress Qfin the film and Ditat the interface. The positive Qfand Ditand a high surface recombination velocity in stacks are observed to increase with the introduced oxygen and minimal hydrogen in the Si Oy Nx film increasing. Prepared by deposition at a low temperature and a low ratio of N2O/Si H4 flow rate, the Si Oy Nx/Si Nx stacks result in a low effective surface recombination velocity（Seff） of 6 cm/s on a p-type 1 ?·cm–5 ?·cm FZ silicon wafer.The positive relationship between Seffand Ditsuggests that the saturation of the interface defect is the main passivation mechanism although the field-effect passivation provided by the fixed charges also make a contribution to it.