Band alignment at the La2Hf2O7/(001)Si interface

In the perspective of exploring alternative gate dielectrics for the future generation of microelectronic devices, we investigated experimentally and theoretically the interface energy barriers induced on (001) silicon by La2Hf2O7, whose growth has been recently attained by molecular-beam epitaxy. Experimental results show that the 5.6 +/- 0.1 eV band gap of La2Hf2O7 is aligned to the band gap of silicon with a valence band offset of 2.4 +/- 0.1 eV and a conduction band offset of 2.1 +/- 0.1 eV. Density functional theory calculations yield valence band offset values ranging between 1.8 and 2.4 eV.