Jae-Hyun Joo

Rugged Metal Electrode (RME) for High Density Memory Devices

Rugged metal electrode (RME) was suggested and evaluated as a bottom electrode of high-density memory capacitors. Rugged ruthenium films (RME-Ru) were successfully fabricated through volume shrinking of ruthenium oxide films under reduction ambient (RuOx+H2=Ru+H2O). The effective surface area of RME-Ru films was significantly enlarged due to the formation of wrinkle on its surface, which resulted in low SiO2 equivalent thickness (Tox) as low as ~ 6 A with Ru/TaOx(110 A)/RME-Ru capacitor. It is believed that RME technique will be very useful to realize and extend MIM (Metal-Insulator-Metal) capacitor era in the mass production of high density memory devices.

Development of CVD-Ru/Ta/sub 2/O/sub 5//CVD-Ru capacitor with concave structure for multigigabit-scale DRAM generation

RIR(Ru/Crystalline-Ta/sub 2/O/sub 5/Ru) capacitor with concave structure was studied for the application into multigigabit-scale DRAM device. In this work, several novel technologies were successfully developed to solve current issues in the fabrication of RIR concave capacitor; such as 1) two-step deposition of Ta/sub 2/O/sub 5/ films 2) formation of Ta/sub 2/O/sub 5/ spacer 3) new separation process of Ru storage node using maskless etch-back method 4) H/sub 2/ pre-annealing and 5) Ar plasma pre-treatment on Ru bottom electrode. The RIR concave capacitor (design rule/spl sim/0.12 /spl mu/m, node height/spl sim/0.85 /spl mu/m) fabricated with these novel technologies showed excellent electrical properties (25fF/cell, 1fA/cell at /spl plusmn/ 1V), which indicates that RIR structure is the one of the most promising candidate for the next generation DRAM capacitor.