High-Quality CVD/Thermal Stacked Gate Oxide Films with Hydrogen-Free CVD SiO2 Formed in a SiCl4–N2O System

Abstract

We have developed and evaluated chemical vapor deposition (CVD) SiO2 films formed in a hydrogen-free system in which tetrachlorosilane ( SiCl4; TCS) and nitrous oxide ( N2O) are used as low pressure CVD source gases. It has been found that the hot-carrier degradation, the constant current time-dependent dielectric breakdown (TDDB) and the charge-trapping characteristics are superior to those of conventional CVD SiO2 films formed from dichlorosilane ( SiH2Cl2; DCS) and N2O. We have concluded that TCS–SiO2 is appropriate for CVD stacked gate oxide films due to its low electron trap density and high reliability.