HfO₂/HfAlO/HfO₂ Nanolaminate Charge Trapping Layers for High-Performance Nonvolatile Memory Device Applications

Abstract

A high-κ HfO2/HfAlO/HfO2 nanolaminate charge trapping layer in a p-Si/SiO2/[HfO2/HfAlO/HfO2 nanolaminate]/Al2O3/platinum memory capacitor has been investigated. High-κ HfO2, Al2O3, and HfO2/HfAlO/HfO2 nanolaminate charge trapping layers are deposited by atomic layer deposition. Well-behaved counter clockwise capacitance–voltage hysteresis characteristics are observed for all memory capacitors. A large memory window of ∼10 V, a very low leakage current density of ∼5×10-9 A/cm2 at a gate voltage of -5 V, a high charge trapping density of ∼1.6×1013/cm2, and a low charge loss of ∼20% after 10 years of retention for the HfO2/HfAlO/HfO2 nanolaminate charge trapping layer are observed as compared with those of pure HfO2 and pure Al2O3 charge trapping layers. Excellent memory characteristics of HfO2/HfAlO/HfO2 nanolaminate layers are obtained owing to the layer-by-layer charge storage. High-κ HfO2/HfAlO/HfO2 nanolaminate charge trapping layers can be used in future nanoscaled high-performance nonvolatile memory device applications.