Nonvolatile floating gate memory containing AgInSbTe-SiO _2 nanocomposite layer and capping the HfO _2/SiO _2 composite blocking oxide layer

摘要

An extremely large memory window shift of about 30.7V and high charge storage density=2.3×10 ~(13)cm ~2 at 23V gate voltage sweep were achieved in the nonvolatile floating gate memory (NFGM) device containing the AgInSbTe (AIST)SiO _2nanocomposite as the charge trap layer and HfO _2/SiO _2as the blocking oxide layer. Due to the deep trap sites formed by high-density AIST nanocrystals (NCs) in the nanocomposite matrix and the high-barrier-height feature of the composite blocking oxide layer, a good retention property of the device with a charge loss of about 16.1% at 15V gate voltage stress for 10 ~4s at the test temperature of 85°C was observed. In addition to inhibiting the Hf diffusion into the programming layer, incorporation of the SiO _2layer prepared by plasma-enhanced chemical vapor deposition in the sample provided a good Coulomb blockade effect and allowed significant charge storage in AIST NCs. Analytical results demonstrated the feasibility of an AIST-SiO _2nanocomposite layer in memory device fabrication with a simplified processing method and post-annealing at a comparatively low temperature of 400°C in comparison with previous NC-based NFGM studies.