Materials science and engineering b-solid state materials for advanced technology vol:109 issue:1-3 pages:74-77
Charge trapping in HfO2 films on Si(1 0 0) was studied using generation of electron-hole pairs in the oxide by 10 eV photons. The oxide deposition chemistry strongly influences the density and sign of the trapped charge: positive charge is observed in films obtained from HfCl4 and metallo-organics, while negative charge is dominant in the films grown from Hf(NO3)(4). The weak dependence of the trapped charge on the HfO2 thickness suggests that charging is associated with a silicon oxide interlayer grown between the Si and HfO2 during deposition. The latter is affirmed by enhancement of the charging after oxidation of the samples at 650degreesC, indicating the interfacial silicon oxide as being the key factor determining the electrical stability of the HfO2 insulating stacks. (C) 2003 Elsevier B.V. All rights reserved.