INNOVATION IN 1T1C FRAM TECHNOLOGIES FOR ULTRA HIGH RELIABLE MEGA DENSITY FRAM AND FUTURE HIGH DENSITY FRAM

Abstract

ABSTRACT FRAM whose cell structure and operation is almost identical to DRAM, can ideally realize cell size and performance of DRAM. However, the density and performance of current FRAM still fall far behind those of DRAM. In this paper, innovative 1T1C FRAM technologies for ultra high reliable mega density FRAMs and future high density FRAMs are discussed. A novel electrode technology has been proved to guarantee 175°C, 10 years retention lifetime and more than 1E13 endurance lifetime of mega density 1T1C, COB FRAM with the cell size of 15F2 at 250 nm technology node. Furthermore, a cell size of 12F2 at 150 nm technology node has successfully been realized by developing innovative 200 nm thick capacitor stack technologies and novel capacitor etching technologies. Finally, critical issues of 3-D capacitor arising from 3-dimensional deposition, such as step coverage and film uniformity have been greatly improved by the modification of the MOCVD PZT feeding source and a newly introduced noble metal atomic layer deposition technology.