On the performance of in situ B-doped P+ poly-Si1-xGex gate material for nanometer scale MOS technology

A study of in situ doped P+ poly-Si1-xGex gate material for the use in nano meter 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 de vices showed no appreciable difference in the direct tunneling current tole rance compared to P+ poly-Si-gated devices. According to SIMS results, no b oron penetration is observed through the oxides, including oxides without n itrogen, after rapid thermal annealing at 900 degrees C for 30 s, 1000 degr ees 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 o f assessing the effect of germanium on the work function of the gate and th us the threshold voltage adjustment for nanometer MOS devices. (C) 2000 Els evier Science Ltd. All rights reserved.