Excellent low-pressure-oxidized Si3N4 films on roughened poly-si for high-density DRAM's

Abstract

High-reliability and good-performance stacked storage capacitors with high capacitance value of 17.8 fF/mu m(2) has been realized using low-pressure-oxidized thin nitride films deposited on roughened poly-Si electrodes. This novel electrodes are fabricated by H3PO4-etched and RCA-cleaned. The leakage current density at +2.5 and -2.5 V are 9.07 x 10(-9) and -2.4 x 10(-8) A/cm(2), respectively, fulfilling the requirements of 256 Mb DRAM's. Weibull plots of time-dependent-dielectric-breakdown (TDDB) characteristics under constant current stress and constant voltage stress also show tight distribution and good electrical properties. Hence, this easy and simple technique is promising for future high-density DRAM's applications.