A combined capacitance-voltage and hard x-ray photoelectron spectroscopy characterisation of metal/Al2O3/In0.53Ga0.47As capacitor structures

Abstract

Capacitance-Voltage (C-V) characterization and hard x-ray photoelectron spectroscopy (HAXPES) measurements have been used to study metal/Al2O3/In0.53Ga0.47As capacitor structures with high (Ni) and low (Al) work function metals. The HAXPES measurements observe a band bending occurring prior to metal deposition, which is attributed to a combination of fixed oxide charges and interface states of donor-type. Following metal deposition, the Fermi level positions at the Al2O3/In0.53Ga0.47As interface move towards the expected direction as observed from HAXPES measurements. The In0.53Ga0.47As surface Fermi level positions determined from both the C-V analysis at zero gate bias and HAXPES measurements are in reasonable agreement. The results are consistent with the presence of electrically active interface states at the Al2O3/In0.53Ga0.47As interface and suggest an interface state density increasing towards the In0.53Ga0.47As valence band edge. (C) 2014 AIP Publishing LLC

Role of Postdeposition Annealing and Doping with Si and Al Impurities in the Formation of HfxSi1–xO2 at the SiO2/FE:HfO2 Interface in a Ferroelectric Field-Effect Transistor

“…The HAXPES results for the Al 1s spectra of the annealed/unannealed Al-doped samples (Figure ) confirm the separation of the Al 2 O 3 –HfO 2 phases after the annealing of the Al-doped sample. Both spectra of the same FWHM correspond well to Al 2 O 3 or AlO x − and exclude the presence of Hf–Al–O since the energy shift relative to the BE of pure Al 2 O 3 corresponding to hafnium aluminate should have a value of 1–1.5 eV close to that for hafnium silicate due to the almost identical electronegativity of Al and Si. , …”

“…Al 1s HAXPES spectra of samples with Al-doped HfO 2 annealed at 850 °C and unannealed measured at 7 keV photon energy. Reference binding energies of Al 2 O 3 , AlO x , Hf–Al–O, and Al-metal states are shown by dashed vertical lines according to refs − (see comments in the text).…”