Low Voltage Operation of High-κ HfO2/TiO2/Al2O3 Single Quantum Well for Nanoscale Flash Memory Device Applications

Abstract

Memory characteristics of the high-κ HfO2/TiO2/Al2O3 single quantum well in a p-Si/Al2O3/HfO2/TiO2/Al2O3/platinum capacitor structure have been investigated. All high-κ films have been deposited by atomic layer deposition. A significant memory window of ∼1.6 V at a low gate voltage operation of 2 V, a high charge storage density of ∼3.6×1012/cm2, a moderate leakage current density of 1×10-6/cm2 at a gate voltage of -2 V, and a negligible charge loss of <5% up to 104 s of retention for the high-κ HfO2/TiO2/Al2O3 single quantum well memory capacitor have been observed as compared with those of pure HfO2, pure TiO2, and pure Al2O3 charge trapping layers. Excellent memory characteristics of the high-κ HfO2/TiO2/Al2O3 single quantum well device are obtained due to charge storage in the quantum well. The high-κ HfO2/TiO2/Al2O3 quantum well device with a low gate voltage operation of <2 V can be used in future nanoscale flash memory device applications.