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

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-κ inter-gate dielectrics and metal floating gate.