Simulation Study of Short Channel Effects in New Hemispherical Gate-All-Around (HGAA) MOS Devices

This work presents a numerical simulation study of short channel effect (SCE) in new hemispherical gate-all-around (HGAA) MOS devices. These new HGAA architectures allow optimizing the gate electrostatic control of simple GAA MOS devices after rounding their channel’s edges with well-defined radius of curvature. The simulation results indicate that the short channel effects (SCE) measured in terms subthreshold swing SS and DIBL can be significantly improved in HGAA structures with smaller silicon curvature radius. It is also found that the gate silicon surface area can be analytically calculated using the Pappus-Guldin theorem and used to model the gate oxide capacitance of such HGAA MOS devices. Pure spherical HGAA structures are also simulated and compared to simple HGAA structures, revealing their excellent performances in terms of SCE, making them ultimate 3D geometry architecture adequate for CMOS integration with the best electrostatic control.