Comparative study of SiO ₂, Al ₂O ₃, and BeO ultrathin interfacial barrier layers in Si metal-oxide-semiconductor devices

In a previous study, we have demonstrated that beryllium oxide (BeO) film grown by atomic layer deposition (ALD) on Si and III-V MOS devices has excellent electrical and physical characteristics. In this paper, we compare the electrical characteristics of inserting an ultrathin interfacial barrier layer such as SiO ₂, Al ₂O ₃, or BeO between the HfO ₂ gate dielectric and Si substrate in metal oxide semiconductor capacitors (MOSCAPs) and n-channel inversion type metal oxide semiconductor field effect transistors (MOSFETs). Si MOSCAPs and MOSFETs with a BeO/HfO ₂ gate stack exhibited high performance and reliability characteristics, including a 34 improvement in drive current, slightly better reduction in subthreshold swing, 42 increase in effective electron mobility at an electric field of 1 MV/cm, slightly low equivalent oxide thickness, less stress-induced flat-band voltage shift, less stress induced leakage current, and less interface charge.