Boron is an excellent dopant for forming germanium (Ge) shallow junctions because of its low diffusivity. This work investigates fabricating heavily boron-doped hydrogenated polycrystalline Ge thin films with an aim to develop a thin p(+) emitter of the bottom cell of a monolithic tandem solar cell. The films were deposited on glass by cosputtering in an argon and hydrogen mixture at 500 degrees C. Rapid thermal annealing at 600 degrees C for 60 s enhances the boron activation level from 6.24 x 10(19) to 1.21 x 10(20) atoms/cm(3). The high activation level obtained with a low thermal budget indicates that the simple fabrication approach is promising. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3473730] All rights reserved.