Charge trapping characteristics of asymmetrical tunnel barriers consisting of different dielectric materials were investigated for application of nonvolatile memory devices. A thin HfO2 layer stacked on ultrathin SiO2 layer (SiO2/HfO2 tunnel barrier) revealed higher current sensitivity to applied gate voltage than the conventional single SiO tunnel barrier. On the other hand, the electron trapping of the tunnel barriers increased with the thickness of HfO2 layer. Thus, a thin HfO2 layer is promising for the engineered tunnel barriers, while a thick HfO2 layer is appropriate for charge trapping layers for high-integrated nonvolatile memories. Meanwhile, an ultrathin Al 2O3/HfO2 tunnel barrier also revealed good electrical characteristics and is suitable for low temperature fabrication process.
ASJC Scopus subject areas
- Physics and Astronomy(all)