Silicate layer formation at Pr2O3∕Si(001) interfaces

We studied Pr2O3∕Si(001) interfaces by synchrotron radiation photoelectron spectroscopy and by ab initio calculations. We show that the interface formed during molecular-beam epitaxy under the oxygen partial pressure above 1×10−8mbar consists of a mixed Si–Pr oxide, such as (Pr2O3)(SiO)x(SiO2)y. Neither an interfacial SiO2 nor an interfacial silicide is formed. The silicate formation is driven by a low energy of O in a PrOSi bond and by the strain in the subsurface SiOx layer. We expect that this natural interfacial Pr silicate will facilitate the integration of the high-k dielectric Pr2O3 into future complementary metal–oxide–semiconductor technologies.