A comparative study of depth profiling of interface states using charge pumping and low frequency noise measurement in SiO2/HfO2 Gate Stack nMOSFETs

Abstract

Charge pumping and low frequency noise measurements for depth profiling have been studied systematically using a set of gate stacks with various combinations of IL and HfO2 thicknesses. The distribution of generated traps after HCl and PBTI stress was also investigated. The drain-current power spectral density made up all of the traps of IL in 0 < z < T-IL and the traps of HfO2 in T-IL < z < T-HK. The traps near the Si/SiO2 interface dominated the 1/f noise at higher frequencies, which is common in SiO2 dielectrics. For the HfO2/SiO2 gate stack, however, the magnitude of the 1/f noise did not significantly change after HCl and PBTI because of more traps in the bulk HfO2 film than at the bottom of the interface. (C) 2009 Elsevier B.V. All rights reserved.