Low voltage stress induced leakage current and time to breakdown in ultra-thin (1.2–2.3 nm) oxides

Ultra-thin gate-oxide reliability is an essential factor in CMOS technologies. The low voltage gate current in ultra-thin oxide of metal–oxide–semiconductor devices is very sensitive to electrical stresses. It can be used as a reliability monitor when the oxide thickness becomes too small for traditional electrical measurements. In this paper, the low voltage stress induced leakage current (LVSILC) for various oxide thicknesses ranging from 1.2 to 2.3 nm is investigated during constant voltage stress (CVS). From the LVSILC measurements, we shown that time to breakdown can be deduced as a function of the stress voltage. We also study the effect of elevated stress temperature on the time to breakdown. We show that temperature dependence of the time to breakdown is non-Arrhenius and decreases in a drastic way with a slope of 0.036 decade/°C.