Enhancement in Electron Mobility at the Interface between Gd2O3(100) and n-type Si(100)

Abstract

An epitaxial growth of a single crystalline gadolinium oxide (Gd2O3) layer with (100) orientation on a p-type Si(100) substrate is obtained when the growth temperature is 200°C and the oxygen partial pressure is in the range of 10-7-10-6 Torr using molecular beam epitaxy technique. The growth on n-type Si(100), on the other hand, results in a polycrystalline structure with a dominant Gd2O3(400) peak observed in the XRD spectrum. Despite a poorer crystal structure, an enhancement in carrier mobility can be found only from the interface between the Gd2O3(100) and n-type Si(100). The mobility of 1730 cm2/V·s was observed at room temperature. This accumulation of the electrons at the interface and the mobility enhancement arise from the two-dimensional confinement due to charges transfer across the interface almost like a transfer doping.