Nanometer scale tunnel oxide fabricated by 'wet nitrous oxide process' for non-volatile memory applications

Abstract

A new oxidation scheme, namely, 'Wet N2O process' for the fabrication of tunnel oxide for flash memory applications has been developed and characterized using both aluminum gate MOS capacitors as well as poly gate MOS capacitors. The Al gate MOS capacitors were electrically characterized under constant field stress conditions for studying reliability and interface properties of the Wet N2O oxide. The poly gate MOS capacitors are electrically characterized and the Stress Induced Leakage Current (SILC) of poly gate MOS capacitors were studied under constant current stress. The results obtained show that the 'Wet N2O oxide' gives excellent interface characteristics and reliability compared to other oxides. The poly gate MOS capacitors show stability and J-E characteristics with extended Fowler-Nordheim region, high breakdown strength and extremely low SLIC when stressed with 35C/cm(2) and therefore ideally suited for application in flash memory devices with tunnel oxides in the nanometer thickness range of 6 nm to 7 nm.