Ferroelectric Nondoped HfO2 Blocking Layer Formation for Hf-based FeNOS Analog Memory Applications

The metal-oxide-nitride-oxide-silicon (MONOS) nonvolatile memories (NVM) are attracting much attention for analog memory applications such as compute-in-memory [1] . The effect of ferroelectric thin films as a blocking layer (BL) or charge trapping layer (CTL) in the MONOS structure has been reported to improve the memory characteristics such as the retention and electron injection efficiency [2] - [4] . We have reported the multi-bit/cell operation of Hf-based MONOS NVM utilizing high-k HfO 2 (HK-HfO 2 ) and HfN 1.1 dielectric layers formed by the in situ process from HfO 2 tunneling layer (TL) to HfN 0.5 gate electrode utilizing electron cyclotron resonance (ECR) plasma sputtering [5] - [6] . In this paper, we have investigated the ferroelectric nondoped HfO 2 (Fe-HfO 2 ) BL formation on the HfN x CTL in the MONOS diode structure for the analog memory application, so called FeNOS, as shown in Fig. 1(a) . The FeNOS would realize the analog control of threshold voltage (V TH ) by the partial polarization of Fe-HfO 2 BL along with the multi-bit/cell operation by the charge trap in the HfN x CTL as shown in Fig. 1(b) .