Published online by Cambridge University Press: 17 June 2014
MOS capacitors with the ZrHfO/AlOx/ZrHfO high-k gate dielectric stack were prepared and characterized for memory functions. The device prefers to trap holes, i.e., under the negative gate voltage, rather than electrons, i.e., under the positive voltage. The hole-trapping process is time and voltage dependent. The weakly trapped holes are quickly released upon the remove of the stress voltage. However, more than 30% of the originally trapped holes can be retained in the device after 10 years. The AlOx embedded ZrHfO high-k stack is a suitable gate dielectric structure for nonvolatile memories.