Low temperature (< 350 degrees C) growth of germanium (Ge) on silicon dioxide (SiO2) is demonstrated using a diborane pretreatment technique. Using SiH4 and B2H6 precursors, Si1-xBx layers are deposited on SiO2 to seed the chemical vapor deposition growth of Ge films. In the SiH4:B2H6 system, the binary deposition mechanism of the Si1-xBx film is explained by the "enhancement" model. In situ doping of Ge films is also investigated. In situ boron activation is achieved during the crystallization of the Ge films at 310 degrees C. Device applicability of the doped Ge film growth on oxide is demonstrated in a low temperature (350 degrees C) Si p-channel metal-oxide-semiconductor field-effect transistor, in which the Ge layer is used as a gate electrode. The low temperature Ge growth technique can be used for low thermal budget processes, e.g., monolithic three-dimensional integrated circuits.