The time/temperature dependencies of the surface roughness, subsurface extended defect formation, and minority-carrier lifetime are reported for n-type (100) silicon wafers exposed to a hydrogen ion beam. Surface roughness is assessed from atomic force microscopy, the distribution and nature of extended defects are determined from transmission electron microscopy, and the minority-carrier lifetime is evaluated by a non-contact laser-microwave technique. The surface roughness exhibits a weak dependence on ion-beam exposure time for the temperature range studied, whereas the distribution of extended defects may depend on exposure time at a given wafer temperature. The surface and bulk components of the minority-carrier lifetimes are consistent with these surface and subsurface properties. Transmission electron microscopy analyses demonstrate that the associated strain field of the extended defects is compressive in nature.