Simulated Dielectric Characteristics of Pt/BST/Ni-Fe/Cu Multilayer Capacitor Stack for Storage Application

摘要

In this simulation research work, the metal-composite-metal (MCM) multilayer capacitor structure [Pt/BST/Ni-Fe/Cu] is proposed with Barium Strontium Titanate (BST) oxide material as the capacitor dielectric material for DRAM with permalloy Nickel-Ferrous (Ni-Fe) coated Copper (Cu) as the bottom conducting electrode and platinum as the top conducting electrode. This proposed MCM consists of 120μm Cu bottom contact material, a 1μm of Ni-Fe alloy over the stoichiometric composition of the BST oxide dielectric material of thickness 40nm and dielectric constant of 775. The MCM structure is expected to deliver a maximum charge storage capacity of 109.75 fF for a capacitor in DRAM cell area of 0.64μm{sup}2 well above the minimum requirement for DRAM cell. The leakage current density for a variation of voltage from 0 to 10V has been simulated for temperature variation. When compared with the previous report, the proposed multi layer capacitor (MLC) structure shows promising potentials in terms of dielectric characteristics.