Field effect surface passivation of SiO 2/Si interfaces by heat treatment with high-pressure H 2O vapor

Abstract

We investigated a simple field effect passivation of the silicon surfaces using the high-pressure H 2O vapor heating. Heat treatment with 2.1×10 6 Pa H 2O vapor at 260°C for 3 h reduced the surface recombination velocity from 405 cm/s (before the heat treatment) to 38 cm/s for the thermally evaporated SiO x film/Si. Additional deposition of 140 nm-SiO x films ( x<2) with a high density of fixed positive charges on the SiO 2/Si samples further decreased the surface recombination velocity to 22 cm/s. We also demonstrated the field effect passivation for n-type silicon wafer coated with thermally grown SiO 2. Additional deposition of 210 nm SiO x films on both the front and rear surfaces increased the effective lifetime from 1.4 to 4.6 ms. Combination of thermal evaporation of SiO x film and the heat treatment with high-pressure H 2O vapor is effective for low-temperature passivation of the silicon surface.