Using Ge-Doped La-Oxynitride as Interfacial Passivation Layer for GaAs Metal-Oxide-Semiconductor Capacitors

Abstract

The GaAs MOS capacitors using ZrON as high-k gate dielectric with LaGeON or LaON as an interfacial passivation layer (IPL) are fabricated and their electrical and interfacial properties are investigated. Compared to their counterpart without IPL, introducing LaGeON or LaON as IPL results in a large improvement of interface quality and electrical properties of the GaAs MOS devices, for example, improved capacitance-voltage behavior, reduced interface-state density and gate leakage current, and enhanced device reliability. Moreover, because of Ge incorporation, the LaGeON IPL becomes more stable and can more efficiently block the Ga/As out-diffusion and O in-diffusion to reduce the defect-related Ga/As-O and As-As bonds at the GaAs surface, thus exhibiting the best interface quality and electrical properties, and high device reliability.