Abstract
AbstractConventional SONOS (polysilicon-oxide-nitride-oxide-silicon) non-volatile memory devices use silicon nitride as the charge storage layer. In this work, metal–oxide–high-k dielectric–oxide–silicon (MOHOS) capacitors and transistors are fabricated using HfO2 and Dy2O3 high-k dielectrics as the charge storage layer. The Al/SiO2/Dy2O3/SiO2/Si capacitors have a C-V memory window of 1.88V. The leakage current density of the Al/SiO2/Dy2O3/SiO2/Si capacitor is 10-8A/cm2 at 10V. The leakage current density of the Al/SiO2/HfO2/SiO2/Si capacitor is 10-6/cm2 at 10V. The leakage current density of the Al/SiO2/Dy2O3/SiO2/Si capacitor is lower than that of Al/SiO2/HfO2/SiO2/Si capacitor at the same bias voltage.The programming speed of Al/SiO2/Dy2O3/SiO2/Si transistor is characterized by a Vth shift of 1.1V with a programming stress pulse voltage of 12V for 10 ms. After a +12V, 0.1 s program pulse and a -12V, 0.5 s erase pulse, the Al/SiO2/Dy2O3/SiO2/Si transistors can keep a ΔVth window of 0.5V for 2x108 seconds. The corresponding numbers for Al/SiO2/HfO2/SiO2/Si transistors are 100 ms and 2x104 seconds. The better performance of the Al/SiO2/Dy2O3/SiO2/Si transistors is attributed to the larger conduction band offset at the Dy2O3/SiO2 interface (2.3eV) versus 1.6eV at the HfO2/SiO2 interface.