The influence of atomic hydrogen on the surface passivation of the Si-SiO2 interface is investigated. Inductively coupled photoconductivity decay measurements indicate an increase in carrier recombination at the surfaces following atomic hydrogen exposure, as measured by an increase in the emitter saturation current density. These defects are not thermally stable and are removed by subsequent thermal treatments above 300 degrees C in N-2. Atomic hydrogen results in the passivation of a certain fraction of thermally stable interface defects. However, the fraction of defects passivated is always slightly lower than can be achieved by exposure to molecular hydrogen. A variation in a sample temperature during atomic H exposure in the range of 25-400 degrees C does not have a significant impact on the passivation efficiency. (C) 2009 The Electrochemical Society. [DOI:10.1149/1.3223586] All rights reserved.