In this work, carbon-added tungsten (W1-xCx, x <= 0.19) and thin carbon layer-inserted tungsten (W-top/C/W-bottom, the thickness of W-bottom is set to be 2 nm and 10 nm) gate stacks are deposited on SiO2/Si to fabricate metal-oxide-semiconductor capacitors. Grazing incident angle X-ray diffraction reveals that the W1-xCx films become amorphous when the concentration of added C is lower than 16 atom %. However, when the C concentration is as high as 19 atom %, a trace of gamma phase of tungsten carbide phase appears in the W0.81C0.19 film. No interdiffusion between C-added W and SiO2 is observed by Auger electron spectroscopy depth profiling. The resistivity of W, W0.88C0.12, W0.84C0.16, and W0.81C0.19 are 132, 151, 163, and 337 mu Omega cm, respectively. The work function of W0.81C0.19, W0.84C0.16, W0.88C0.12, W, W/C/W (10 nm), and W/C/W (2 nm) on SiO2 are 4.82, 4.75, 4.73, 4.66, 4.52, and 4.32 eV, respectively. The C-related dipole shows apparent influence on the work function. The leakage current densities of C-added W films are smaller than 2 x 10(-5) A/cm(2) in the range from 0 to 5 x 10(7) V/cm. No significant influence of these gate electrodes on the fixed oxide charge and the leakage behavior of SiO2 are observed. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3524268] All rights reserved.