High-k materials and their response to gamma ray radiation

The radiation response of four different high-k materials has been investigated by irradiating them using a 979 MBq Cs-137 gamma-ray source and a dose absorption rate of 0.71 rad(Si)/s. Acceptorlike electron traps and donorlike traps were observed in HfO2 and ZrO2 metal-oxide-semiconductor capacitors originating from radiation-induced defects. A lower density of donor-like traps were created in LaAlO3 and NdAlO3 capacitors, but both electron and hole trapping play a role in shifting the flat band voltage. The radiation hardness of the LaAlO3 and NdAlO3 thin films is similar to thermal SiO2 but better than the HfO2 and ZrO2. (C) 2009 American Vacuum Society. [DOI: 10.1116/1.3071848]