We investigated the electrical properties and microstructures of n-type doped poly Si1-xGex films with Ge contents using hall measurement, four-point probe, transmission electron microscopy, and energy dispersive X-ray spectrometry to apply to gate electrode of complementary metal oxide semiconductor field effect transistor. The sheet resistance of poly Si1-xGex films implanted with arsenic decreased with the decrease of Ge content and the increase of activation temperature due to the increase of carrier mobility and activated carrier concentration. In addition, we found that the segregation of dopant increased at the grain edge and the activated carrier concentration decreased with the increase of Ge content due to higher diffusivity and lower solid solubility limit of As in poly Si1-xGex films. (C) 2003 The Electrochemical Society.