Selective phase growth of van der Waals high-κ Sb2O3 films

Abstract

van der Waals (vdW) dielectric films are characterized by their dangling-bond free interface and thus show promise for use as the gate in the next-generation field effect transistor devices. The molecular crystal Sb₂O₃ has been proved to be an effective high-κ vdW dielectric with low-cost and CMOS compatibility. However, fabricating wafer-scale Sb₂O₃ films with a controllable dielectric constant and crystal phase is challenging. Based on the results of a first-principles study, we designed an oxygen-assisted low temperature pulsed laser deposition (PLD) method for the phase-selective growth of α- and β-Sb₂O₃ thin films with super-high κ (>100) and good homogeneity. The phase control is experimentally demonstrated by tuning the oxygen gas pressure during the growth process. Dielectric analysis of pure phase α-Sb₂O₃ shows excellent dielectric properties and reveals the physics of the transport mechanism and dielectric relaxation process.