Atomic structure and thermally induced transformation of the crystalline BaO/Si(100) junction

Atomic structure of interfaces between oxide layers and semiconductors is usually challenging to probe because of its buried nature. Here, we present a synchrotron photoemission approach to unveil the interface structure of BaO/Si(100), a prototype model of crystalline-oxide/semiconductor junctions, and demonstrate that such interface outspreads over four Si atomic planes and contains five different crystal sites for Si atoms, including three Si-O bonding sites. An atomic model is suggested for this system. Heating enhances Si diffusion and oxidation, but the junction still remains crystalline at 500 [degrees]C, promising potential for integration of III-V films and Si(100).