Analytical Formulation of SiO2-IL scavenging in HfO2/SiO2/Si gate stacks - A key is the SiO2/Si interface reaction

The scavenging kinetics of ultra-thin-SiO₂ interface layer (IL) in HfO₂/SiO₂/Si stacks is investigated by focusing on SiO₂/Si interface reaction in addition to both O and Si atom kinetics. SiO₂/Si interface serves as a stage that the oxygen vacancy (VO) is converted to Si release from SiO₂ with the help of Si substrate. Based on both diffusion kinetics and possible reaction, an analytical model for two-stage SiO₂-IL scavenging in high-k gate stack is proposed.