Inverse-Vg Dependence of PBTI Lifetime of HfSiON Gate Dielectrics Measured by a High-Temperature Pulsed-IV Method

Abstract

This paper describes a new NBTI/PBTI evaluation method which uses high-temperature pulsed IV. The benefit of this method is that because the bulk charge is detrapped during the interval before each measurement sequence, only the interfacial component can be extracted. PBTI lifetime of HfSiON, when measured by pulsed IV, is found to be on the line of log(t) vs 1/Vg, contrary to NBTI lifetime which is defined by log(t) vs Vg. Moreover, it is found that temperature dependence of PBTI is smaller than that of NBTI. These findings lead to the conclusion that electric field, rather than thermodynamic energy, affects the reaction at/near Si interface under PBTI stress. PBTI lifetime of TaSiN/HfSiON becomes larger than NBTI lifetime of TiN/HfSiON because of the different Vg dependence.