Epitaxial growth and thermal stability of silicon layers on crystalline gadolinium oxide

In this work, an unconventional approach for epitaxial growth of Si on single-crystalline rare-earth oxide is presented using molecular beam epitaxy under ultra-high vacuum. Surface and bulk crystalline structures as well as chemical content were examined. Silicon-on-insulator layers were fabricated by encapsulated solid phase epitaxy on Si(111) substrate. The gadolinium oxide capping layer was removed by wet-chemical etching. The remaining silicon layer is single crystalline without any impurities and exhibits 7 × 7 reconstructed surface after annealing in very low silicon flux in the growth chamber. The thermal stability of the fabricated silicon-on-insulator structure was studied by step-wise heating under ultra-high vacuum conditions. The fabricated ultra-thin (10-15 nm) silicon-on-oxide layers remain structurally and chemically stable up to 900 °C.