摘要
High-k materials are used to replace traditional gate dielectric SiO2 to overcome the tunneling limit[1;2].However,large concentrations of traps can be generated in high-k dielectrics by ion irradiation in the space environment,thus degrade the device performance[3].In this paper,we report on charge transfer(trapping and detrapping)mechanisms in ultrathin HfO2-based MOS capacitors under heavy ion irradiation(Fig.1).The un-packaged samples were irradiated by 4 MeV Xe ions to a fluence of 11013 ions/cm2 without electrical bias.The capacitance-voltage(C-V)characteristics of the devices before and after irradiation were performed using Keithley 4200 integrated system analyzer and shielding probe station at 100 kHz AC frequency.The experimental results show that HfO2-based MOS devices are greatly influenced by heavy ion irradiation.
