Enhancement of Nonvolatile Floating Gate Memory Devices Containing AgInSbTe-SiO₂ Nanocomposite by Inserting HfO₂/SiO₂ Blocking Oxide Layer

Abstract

This work presents an enhancement of nonvolatile floating gate memory (NFGM) devices comprised of AgInSbTe (AIST) nanocomposite as the charge-storage trap layer and HfO 2 or HfO 2 /SiO 2 as the blocking oxide layer. A significantly large memory window (ΔV FB) shift = 30.7 V and storage charge density = 2.3×10 13 cm −2 at ±23V gate voltage sweep were achieved in HfO 2 /SiO 2 /AIST sample. Retention time analysis observed a ΔV FB shift about 19.3 V and the charge loss about 13.4% in such a sample under the ±15V gate voltage stress after 10 4 sec retention time test. Regardless of applied bias direction, the sample containing HfO 2 /SiO 2 layer exhibited the leakage current density as low as 150 nA/cm 2 as revealed by the current-voltage (I-V) measurement. This effectively suppresses the electron injection between gate electrode and charge trapping layer and leads to a substantial enhancement of NFGM characteristics.