We investigated the effect of boron dosage and post-thermal budget on the electrical properties such as capacitance-voltage (C-V), gate leakage current-voltage (I-V), and charge-to-breakdown (Q(BD)) of metal oxide semiconductor (CMOS) capacitors with W/WNx/poly-Si1-xGex gates stack. The C-V curve of the MOS-capacitors with the W/WNx/poly-Si0.4Ge0.6 stack had a lower flatband voltage (V-FB) and showed less gate depletion effect (GDE), compared with that of the W/WNx/poly-Si0.8Ge0.2 stack due to the decrease of gate electrode work function and the increase of dopant activation rate with the increase of Ge content, respectively. Although the I-V curves of MOS-capacitors with W/WNx/poly-Si1-xGex gates stack exhibited similar behaviors regardless of Ge content, the beginning of conduction in the I-V curves accelerated with the increase of Ge content due to the decrease of the gate electrode work function. The Q(BD) of W/WNx/poly-Si0.4Ge0.6 gates stack was much higher than that of the W/WNx/poly-Si gates stack due to the reduced boron penetration in the gate oxide. We also found that annealing temperatures between 800 and 850degreesC had no influence on the electrical properties of MOS capacitors with W/WNx/poly-Si1-xGex gates stack. (C) 2003 The Electrochemical Society.