Experimental estimation of charge neutrality level of SiO2

The charge neutrality level of SiO2 is experimentally extracted by investigating conduction band offset (CBO) of SiO2/Si stack with different SiO2 thicknesses using X-ray photoelectron spectroscopy. The CBO is found to be dependent on SiO2 thickness. The CNL of SiO2 is determined to be 4 eV above valence band maximum by modeling the CBO vs. thickness of SiO2 using gap states and charge neutrality level based model.