Suppression of dielectric crystallization on metal by introduction of SiO_2 layer for metal floating gate memory blocking oxide

摘要

A technique of reducing the higher degree of dielectric crystallization on polycrystalline metal has been investigated by inserting a thin SiO_2 layer interfacing the metal for application as high-k blocking oxide in metal floating gate FLASH memories. Grazing incidence x-ray diffraction study showed that the insertion of an amorphous interfacial layer (IL) suppresses the crystallization of HfAlO blocking oxide considerably. The electrical performance of the blocking oxide stacks was characterized using metal-insulator-metal capacitors, and the thermal stability was observed to improve by more than an order of magnitude with the incorporation of SiO_2 IL.