Designer hydride routes to ‘Si–Ge’/(Gd,Er)2O3/Si(1 1 1) semiconductor-on-insulator heterostructures
We demonstrate Si?Ge integration on engineered M2O3/Si(1?1?1) (M = Gd,Er) dielectric buffer layers using non-traditional chemical precursors that provide new levels of functionality within the deposition process. Stoichiometric Si0.50Ge0.50 alloys and pure Si heterostructures are grown epitaxially via ultra-low-temperature chemical vapor deposition using SiH3GeH3 and Si3H8/Si4H10, respectively. In the case of Si on Gd2O3, an optimal growth processing window in the range of 500?600 ?C was found to yield planar layers with monocrystalline structures via a proposed coincidence lattice matching mechanism (2aSi?aGd2O3), while for the SiGe system (2% lattice mismatch) comparable quality films with fully relaxed strain states are deposited at a lower temperature range of 420?450 ?C. Extension of this growth process to Si on Er2O3 yields remarkably high-quality layers in spite of the even larger ~3% lattice mismatch. In all cases, the Si?Ge overlayers are found to primarily adopt an A?B?A epitaxial alignment with respect to the M2O3 buffered Si(1?1?1). A comparative study of the Si growth using Si3H8 and Si4H10 indicates that both compounds provide an efficient and straightforward process for semiconductor growth on Gd2O3/Si(1?1?1), which appears to be more viable than conventional approaches from the point of view of scalability and volume.