Reliability constraints for TANOS memories due to alumina trapping and leakage

In this work we present a detailed investigation of TANOS memory reliability, focusing on issues raised by Al
₂
O
₃
trapping/detrapping and leakage. These effects are investigated as a function of alumina thickness, electric field and temperature, comparing experimental and modeling results for trap parameters extraction. For TANOS devices, Al
₂
O
₃
charge storage modifies program and erase saturation level particularly when higher Al
₂
O
₃
thikness are considered. Threshold instability in early steps for endurance and retarded behavior for retention can be also ascribed to the Al
₂
O
₃
trapping. Moreover, Al
₂
O
₃
layer has been shown to provide the main leakage path for bottom oxides thickness in the 4.5 nm or above range.