Determination of Adsorption Layers on Silicon Sorption Artifacts using the Gravimetric Method

Abstract

The adsorption layers on the surface of silicon artifacts were determined experimentally as a function of relative air humidity in the range of 0.07 \ h \ 0.73 using the gravimetric method. 1 kg silicon sorption artifacts were fabricated with the same surface finish and material properties, but they had a very different surface area of 507.8 cm 2 .I n this experiment, an ultra-precision mass comparator and special humidity control unit were used. We found that the sorption behavior of the silicon surface was type II by BET classification with the parameters lm = 0.017 lg/cm 2 , and cB = 9.3 from the adsorption isotherm of water vapor on the surface of silicon with Rz \ 26.6 nm. The coefficient of water vapor adsorption in moist air was estimated as dl/dh = 65.3 ng cm -2 in a limited humidity range of 0.3 \ h \ 0.6.