A stacked capacitor technology with ECR plasma MOCVD(Ba,Sr)TiO3 and RuO2/Ru/TiN/TiSixstorage nodes for Gb-scale DRAMs |
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| Authors: | Yamamichi S Lesaicherre P Yamaguchi H Takemura K Sone S Yabuta H Sato K Tamura T Nakajima K Ohnishi S Tokashiki K Hayashi Y Kato Y Miyasaka Y Yoshida M Ono H |
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| Affiliation: | Fundamental Res. Labs., NEC Corp., Kawasaki; |
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| Abstract: | A Gb-scale DRAM stacked capacitor technology with (Ba,Sr)TiO3 thin films is described, The four-layer RuO2/Ru/TiN/TiSix, storage node configuration allows 500°C processing and fine-patterning down to the 0.20 μm size by electron beam lithography and reactive ion etching. Good insulating (Ba0.4Sr0.6)TiO3 (BST) films with an SiO2 equivalent thickness of 0.65 nm on the electrode sidewalls and leakage current of 1×10-/6 Acm2 at 1 V are obtained by ECR plasma MOCVD without any post-deposition annealing, A lateral step coverage of 50% for BST is observed on the 0.2 μm size storage node pattern, and the BST thickness on the sidewalls is very uniform, thanks to the ECR downflow plasma. Using this stacked capacitor technology, a sufficient cell capacitance of 25 fF for 1 Gb DRAMs can be achieved in a capacitor area of 0.125 μm2 with only the 0.3 μm high-storage electrodes |
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