Impact of Quantum Confinement on Stress-Induced nMOSFET Threshold Voltage Shift

In this paper, we propose a comprehensive model to express nMOSFET threshold voltage shift induced by stress, ranging from a high tensile one to a high compressive one. Using this model, the quantum confinement effect, combined with large out-of-plane stress, is shown to play an important role to cause the threshold voltage shift as large as about 80 mV induced by high-film-stress contact etch-stop layer.