2-bit poly-Si-TFT nonvolatile memory using hafnium oxide, hafnium silicate and zirconium silicate

In this paper, the authors, for the first time, have successfully fabricated SONOS-type poly-Si-TFT memories employing three kinds of high-k dielectrics, including HfO
₂
, Hf-silicate and Zr-silicate, as the trapping layer with low-thermal budget processing. It was demonstrated that the fabricated memories exhibit good performance in terms of relatively large memory window, high program/erase speed (1ms/10ms), long retention time (>10
⁶
s for 20% charge loss) and negligible read/write disturbances. In particular, 2-bit operation has been successfully demonstrated