IMPROVED NON-DESTRUCTIVELY READ FERROELECTRIC MEMORY CELL

摘要

An improved ferroelectric FET structure (10) in which the ferroelectric layer (14) is doped to reduce retention loss. A ferroelectric FET according to the present invention includes a semiconductor layer (16) having first and second contacts (18, 19) thereon, the first and second contacts being separated from one another. The ferroelectric FET also includes a bottom electrode (12) and a ferroelectric layer (14) which is sandwiched between the semiconductor layer (16) and the bottom electrode (12). The ferroelectric layer (14) is constructed from a perovskite structure of the chemical composition ABO3 wherein the B site comprises first and second elements and a dopant element that has an oxidation state greater than +4 in sufficient concentration to impede shifts in the resistance measured between the first and second contacts with time. The ferroelectric FET structure preferably comprises Pb in the A-site. The first and second elements are preferably Zr and Ti, respectively. The preferred B-site dopants are Niobium, Tantalum, and Tungsten at concentration between 1 % and 8 %.