Ultrathin Si capping layer suppresses charge trapping in HfOxNy∕Ge metal-insulator-semiconductor capacitors

In this study the authors investigated the Ge outdiffusion characteristics of HfOxNy∕Ge metal-insulator-semiconductor capacitors to determine their charge trapping behavior. Capping the Ge substrate with an ultrathin Si layer inhibits the incorporation of Ge into the high-k bulk dielectric in the form of GeOx, thereby diminishing the resultant oxide charge trapping. The thermal stability of the entire capacitor structure was also improved after performing an additional Si passivation process.