Epitaxial growth of single crystalline lattice-matched Pr0.9Y1.1O3 on SrO-passivated Si001: growth orientation and crystallization tailoring by interface engineering

In this work, SrO buffer layers were employed as an interface engineering approach to realize single crystalline mixed ternary rare earth bixbyite oxide (RE2O3) films on Si (001) substrate. Single crystalline mixed PrxY2-xO3 (x=0-2) has been successfully grown on Si (111) (Ref. 7). However, the formation of such mixed oxide can only be realized at >750 °C, therefore when it is directly grown on Si (001) PrxY2-xO3 is polycrystalline due to the formation of an amorphous silicate or SiO2 interfacial layer on Si (001). A 1/2 monolayer (ML) SrO buffer layer can effectively prevent the interface reaction thus it allows realizing single crystalline ternary mixed Pr0.9Y1.1O3 films on Si (001). This fully lattice-matched RE2O3 film demonstrates 110 orientation on Si (001). Furthermore, SrO buffer layers are not only important to control the single crystallinity but also the growth orientation and crystallization behaviour of ternary RE2O3 films. A 111-oriented, phase separated Pr2O3-Y2O3 film was obtained under identical growth conditions by simply increasing the thickness of SrO buffer layer to 3 ML.