A study of in situ doped P+ poly-Si1-xGex gate material for the use in nanometer scale MOS technology is presented. P+ poly-Si1-xGex-gated MOS devices, with x = 0%, 20%, or 35% and O-2- and NO-grown ultrathin gate oxides (2.3-3.0 nm), were fabricated for this investigation. P+ poly-Si1-xGex-gated devices showed no appreciable difference in the direct tunneling current tolerance compared to P+ poly-Si-gated devices. According to SIMS results, no boron penetration is observed through the oxides, including oxides without nitrogen, after rapid thermal annealing at 900 degrees C for 30 s, 1000 degrees C for 10 s, and furnace annealing at 850 degrees C for 40 min. Using C-V measurements, we found that in situ doping provides a more accurate way of assessing the effect of germanium on the work function of the gate and thus the threshold voltage adjustment for nanometer MOS devices.