Interface Optimization and Band Alignments of HfTiO/InGaAs Gate Stacks by Metalorganic Chemical Vapor Deposition of AlON Passivation Layer

In this report, the reduction and removal of surface native oxides.(GaOx, AsOx) from the as-received In GaAs surface by using dimethylaluminumhydride (DMAH)-derived AlON passivation layer with self-cleaning effect prior to HfTiO deposition is reported to solve Fermi level pinning challenge. XPS analysis has revealed that complete consumption of native oxides of AsOx and GaOx at the InGaAs surface, but no effect to InOx, has been realized by MOCVD AlON at 300 degrees C. Meanwhile, the regrowth of the native oxides at the interface of HfTiO/InGaAs gate stacks has been detected by inserting AlON passivation layer. Valence band spectra of HfTiO/AlON/InGaAs gate stacks show reduction in valence band offset and increase in conduction band offset compared to that of HfTiO/InGaAs. The improved interface control and suitable band offset relative to InGaAs make HfTiO/AlON/InGaAs as promising gate stacks in future InGaAs-based MOSFET devices.