SI3N4 THICKNESS AND ITS OXIDATION TIME INFLUENCE ON O N/O DRAM CELL PERFORMANCE/

In dynamic random access memory (DRAM) devices the cell capacitance pe rformance is considered one of the main properties from a reliability stand point. The cell can lose the stored charge because of many leaka ge currents. One of them depends on the quality of the materials used to form the capacitor itself. In trench technology the most used capac itor is a stacked layer made of silicon nitride and oxide: SiO2/Si3N4/ SiO2. The first silicon oxide is a native layer grown during the push of the wafers in the thermal reactor used to deposit the nitride layer ; the second oxide is a layer grown during the thermal oxidation of ni tride film. In the paper the influence of silicon nitride thickness an d second oxide on the final device yield is studied together with the changes in cell performance (capacitance, breakdown voltage and curren t). (C) 1997 Elsevier Science B.V.