Investigation of degradation behavior under negative bias temperature stress in Si/Si0.8Ge0.2 metal-oxide-semiconductor capacitors

Abstract

In this paper, capacitance and conductance characteristics are used to explain reliability issues in metal-oxide-semiconductor capacitors (MOSCAPs) with a silicon-germanium (SiGe) channel. The SiGe channel devices are also comprehensively compared to traditional Si channel devices. After negative bias temperature stress, both exhibit flat-band voltage (V FB) shifts in the negative direction and a rise in the conductance hump. Generally, the process of Si devices is more stable than SiGe devices, resulting in the interface quality of Si MOSCAPs being better due to lattice constant matching at the interface. However, it is noteworthy that the degradation of Si MOSCAPs is more serious than that of Side MOSCAPs. Therefore, this study quantitatively extracts the interface defects and illustrates the generation of interface defects with a reaction-diffusion model. In addition, the difference in the injected energy level is used to explain the difference in the VFB shift.