Defects characterization of Hybrid Floating Gate/Inter-Gate Dielectric interface in Flash memory

摘要

In this work we characterize the Hybrid Floating Gate (HFG) / Inter-Gate Dielectric (IGD) interface by means of electron charging / discharging from the inter-gate dielectrics layer to the floating gate using a fast response technique (Interface Characterization by Programming and Sensing “ICPS”) in Flash memory devices. The technique is applied to dedicated samples such as Al2O3, HfAlO, ScAlO, as single layer and three-layered inter-gate dielectric stacks HfAlO/Al2O3/HfAlO, HfAlO/SiO2/HfAlO on either Poly-Si or Si/TiN Floating Gate (FG). The results show that the electron charging /discharging at hybrid floating gate / inter-gate dielectric using ICPS and at the inter-gate dielectric / control gate interface using Gate-Side-Trap Spectroscopy by Charge Injection and Sensing (GS-TSCIS) technique is independent of the deposition order for a given metal. Additionally, this charge transition process leading the electron charging / discharging instability, occurs within ms range and can continue for seconds. More importantly, this fast charge transition can be suppressed by using optimized high-к inter-gate dielectrics and metal floating gate.