Doped HfO2-based ferroelectric-aided charge-trapping effect in MFIS gate stack of FeFET.

The ferroelectric field effect transistor (FeFET) is a very promising candidate for low-power and non-volatile memory. However, the co-existing effect of ferroelectric polarization and interface charge trapping in the FeFETs is demonstrated and many efforts have been made to eliminate this charge-trapping effect, which is usually treated as a deleterious effect. In contrast, we have found that the charge-trapping effect can play a dominant role in ferroelectric gates. In this work, we have verified that the charge-trapping effect of the ferroelectric/insulator interface could induce a memory window as the main physical mechanism in the TiN/Hf_0.5Zr_0.5O₂/SiO₂/p-Si (MFIS) structure, in which the ferroelectric characteristics of HZO thin films was verified through a reverse-grown MFIS structure. We also demonstrated that 2.5 nm SiO₂ is optimal for the charge tunneling effect and the device has the largest memory window. Moreover, in order to enlarge the memory window of MFIS capacitors, we utilized the stress-enhanced ferroelectric polarization characteristics of Hf_0.5Zr_0.5O₂ to improve the charge-trapping effect. Such a finding demonstrates that the ferroelectric-aided charge-trapping devices are potential to be used in non-volatile memories. [ABSTRACT FROM AUTHOR]