XPS Study on Chemical Bonding States of High-k Gate Stacks for Advanced CMOS

摘要

The paper reviews the non-destructive depth profiling of the composition and the chemical structure of high-K/Si using angle-resolved photoelectron spectroscopy. Analyses of Si 2s spectra show that the reactivity between ScOx or CeOx and Si substrate is lower than that between LaOx and Si substrate. Analyses of Ce 3ds/2 and O ls spectra show that a oxidation state of Ce changes from Ce~(4+) to Ce~(3+) by PDA in N_2 at and above 400°C and changes from Ce~(3+) to Ce~(4+) by PDA in O_2 at 300°C. This implies that a oxidation state of Ce can be controlled by changing the condition of PDA. The hard X-ray(hv = 8 keV) excited ARXPS study on high-K/Si structure show that the existence of La-silicate accelerates the formation of La-silicate by PDA.