Ultra-Thin TiN/Ta,OJW Capacitor Technology for 1GBit DRAM

A highly reliable TqO, (1.6nm SiO, equivalent thickness) capacitor with TiNRqOJW structure is developed for lGbit DRAMs. This TqO, capacitor formed on the enlarged area electrode achieves a cell capacitance of 30fF with 0.6pm-height storage-node in a area of 0.24pm'. The critical steps in this technology are using of tungsten (W) for the storage-node surface, oxygen-plasma annealing after TqO, film deposition, and a hemi-spherical grained (HSG) Si before W film deposition. This 1.6nm SiO, equivalent thick TqO, capacitor on HSG Si structure is realized at half of 1.5V operation voltage with 10-*A/cmZ leakage current density.