Title :
A stacked capacitor technology with ECR plasma MOCVD (Ba,Sr)TiO3 and RuO2/Ru/TiN/TiSix storage nodes for Gb-scale DRAMs
Author :
Yamamichi, Shintaro ; Lesaicherre, Pierre-Yves ; Yamaguchi, Hiromu ; Takemura, Koichi ; Sone, Shuji ; Yabuta, Hisato ; Sato, Kiyoyuki ; Tamura, Takao ; Nakajima, Ken ; Ohnishi, Sadayuki ; Tokashiki, Ken ; Hayashi, Yukihiro ; Kato, Yoshitake ; Miyasaka, Yo
Author_Institution :
Fundamental Res. Labs., NEC Corp., Kawasaki, Japan
fDate :
7/1/1997 12:00:00 AM
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
Keywords :
DRAM chips; barium compounds; capacitors; dielectric thin films; electron beam lithography; elemental semiconductors; leakage currents; plasma CVD coatings; ruthenium; ruthenium compounds; silicon; sputter etching; strontium compounds; titanium compounds; (BaSr)TiO3-RuO2-Ru-TiN-TiSi-Si; 0.20 micron; 25 fF; 500 degC; ECR plasma MOCVD; Gb-scale DRAMs; capacitor area; cell capacitance; downflow plasma; electrode sidewalls; electron beam lithography; fine-patterning; lateral step coverage; leakage current; reactive ion etching; stacked capacitor technology; storage nodes; Binary search trees; Capacitors; Electrodes; Electron beams; MOCVD; Plasma applications; Plasma materials processing; Random access memory; Tin; Transistors;
Journal_Title :
Electron Devices, IEEE Transactions on
