The first experimental observations were made of electrically biased paramagnetic defects in 800C N2 annealed HfxSi1−xO2 (x = 0.4, and 0.6)/(100)Si and HfO2/(100)Si interfaces in metal oxide silicon structures. These defects were examined by electrical-field controlled electron spin resonance and correlated with capacitance-voltage (C-V) analysis. Distributions of electron spin resonance measured density of interface traps (ESR-Dit), Pb0 and Pb1, exhibited distinct charge humps and peaks in the Si band-gap with maximum defect density of 0.9–1.9 x 1012/cm2eV in the Hf0.4Si0.6O2/Si interface. Three Pb0 and one Pb1 charged ESR-Dit peaks with density of 1.7–2.8 x 1012/cm2eV were observed in the Hf0.6Si0.4O2/Si interface. Cross-sectional transmission electron microscopic images show decreasing interfacial layer thickness with increasing hafnium composition (x) at the HfxSi1−xO2/Si interface. The roughest interfacial layer observed at the HfO2/Si interface may have contributed to an ESR-Dit of Pb0 greater than 2 x 1013/cm2eV and a pinned Fermi level near the mid-gap. It appears that the energy distributions of interface defects in HfxSi1−xO2/Si and HfO2/Si have different signatures compared to those at SiO2/Si interface, especially the charged peak near the mid-gap.

Analysis of Electrically Biased Paramagnetic Defect Centers in HfO2 and HfxSi1−xO2/(100)Si Interfaces. P.T.Chen, B.B.Triplett, J.J.Chambers, L.Colombo, P.C.McIntyre, Y.Nishi: Journal of Applied Physics, 2008, 104[1], 014106