Nature of Interface Traps in Si/SiO_2/HfO_2 /TiN Gate Stacks and its Correlation with the Flat-Band Voltage Roll-Of

摘要

We have carried out a detailed experimental investigation of the trap parameters - trap energy, trap density, and hole capture cross-section - in a large number of p-Si/SiO_2/HfO_2/TaN MOS capacitors fabricated on wafers with graded SiO_2 layer, and of the flat-band voltage, using a newly developed admittance spectroscopy technique, which yields accurate values of the surface potential and the flat-band voltage, and makes use of the measured conductance to obtain accurate values of the trap parameters. The correlation, if any, between the trap density and the flat-band voltage has been analyzed.