Experimental Determination of the Band Offset of Rare Earth Oxides on Various Semiconductors

Part of the Topics in Applied Physics book series (TAP, volume 106)


The critical role of gate oxide in ultra-scaled devices is being investigated in terms of the properties of rare earth oxides as high dielectric constant (high-κ) materials to replace SiO2. In particular, the combination of rare earth oxides with high-mobility substrates, like Ge and GaAs, could offer the possibility to improve the interface properties. Among the different properties under investigation, the band alignment at the interface is a key issue because it affects the tunneling behavior of a device. Internal photoemission and X-ray photoelectron spectroscopy are useful techniques to experimentally determine the band offset at the semiconductor/oxide interface. After a detailed description of these two methods, we present a review of the data available in the literature on the interface of different high-κ oxides on silicon. Finally, we report our measurements of the Lu2O3 band alignment on various semiconductor substrates. A conduction band offset value of 2.1 eV has been obtained by internal photoemission for Lu2O3 films grown on Si, Ge, and GaAs. X-ray photoelectron spectroscopy measurements of the valence band offset were performed on Ge/Lu2O3 heterojunction. The results are in excellent agreement with those obtained using internal photoemission.


71.55.-i; 72.80.Sk; 73.20.At; 75.47.Lx; 77.55.+f 


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Authors and Affiliations

  1. 1.CNR-INFM MDM National LaboratoryAgrate Brianza (MI)Italy

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