The Electrical Property of CeO_2 Films Deposited by MOCVD on Si(100)

摘要

Cerium dioxide (CeO_2) films were prepared by chemical vapor deposition (CVD) using tetrakis(3-methyl-3-pentoxy)cerium, Ce[OC(C_2H_5)_2CH_3]_4. The capacitance-voltage' (C-V) characteristics of an as-deposited CeO_2 metal-insulator-semiconductor (MIS) capacitor represented a large flatband voltage shift of 1.0 V as well as a large hysteresis of 1.0 V. After annealing at a rather low temperature of 500 deg C, the C-V characteristics were improved remarkably. The hysteresis decreased to 0.15 V and the flatband voltage shift almost disappeared. The slope of the C-V curve near the flatband voltage for the annealed samples became steep, especially after annealing in the oxidizing ambient. The leakage current decreased by four orders of magnitude after annealing in O_2 and even more in the O-radical ambient. The resultant CeO_2 on Si had the dielectric constant of 18.0, equivalent to the HfO_2 film, and also as low leakage current of 1.0 X 10~(-7) A/cm~2 as Hf silicate.