Properties of heavily boron-doped hydrogenated polycrystalline germanium (Ge) films sputter-deposited on glass are investigated for developing p(+) emitters of the bottom cells of low cost monolithic tandem solar cells. The films were deposited and in-situ doped by co-sputtering Ge with boron at various power levels (P-B) in a mixture of argon and hydrogen at 500 degrees C, and then followed by a rapid thermal anneal process at 550 degrees C for 120 s or 600 degrees C for 60 s, respectively. The dependence of the structural properties of the films on the various boron incorporations as well as annealing conditions was explored by Raman and X-ray diffraction measurements. We find that the films as deposited at 500 degrees C are polycrystalline with strong (2 2 0) preferential orientation, which are normally of columnar structure, confirmed by cross-sectional transmission electron microscopy. Revealed by Hall measurements, a boron activation level of 6.24 x 10(19) atoms/cm(3), well above reported maximum solid solubility in crystalline Ge, was obtained in the as deposited film at P-B=55 W. Annealing at 600 degrees C enhanced the concentration to 1.21 x 10(20) atoms/cm(3). A fact that boron hardly diffuses in Ge at temperatures below 800 degrees C makes the resultant material an excellent candidate for thin p emitters of the bottom cells of monolithic tandem solar cells. (C) 2010 Elsevier B.V. All rights reserved.