Evidence is presented that hydrogen preferentially passivates silicon dangling bonds in the grain boundaries of narrow thin-film polycrystalline resistors patterned by a plasma etching process. While these effects are well known qualitatively, we present quantitative measurements which include resistance and thermal activation energy of resistance measurements on small resistors and blanket films with varying boron doping levels and process conditions. The most likely origin of the hydrogen which causes these observed passivation effects is the plasma etch process which was used to define the resistors from a blanket film