Title :
A stacked capacitor with (Ba/sub x/Sr/sub 1-x/)TiO/sub 3/ for 256M DRAM
Author :
Koyama, K. ; Sakuma, T. ; Yamamichi, S. ; Watanabe, H. ; Aoki, H. ; Ohya, S. ; Miyasaka, Y. ; Kikkawa, T.
Author_Institution :
NEC Corp., Sagamihara, Japan
Abstract :
A high-dielectric-constant material was applied to a practical stacked DRAM capacitor. A large unit area capacitance (40 fF/ mu m/sup 2/) and a low leakage current (<10/sup -7/ A/cm/sup 2/) have been realized by the combination of a thin (Ba/sub x/Sr/sub 1-x/)TiO/sub 3/ film having an equivalent SiO/sub 2/ thickness of 8 AA and a Pt/Ta capacitor electrode. TDDB (time-dependent dielectric breakdown) measurements have indicated good reliability of this novel capacitor cell. These characteristics show that this storage capacitor is quite promising for 256M DRAM cells.<>
Keywords :
DRAM chips; barium compounds; capacitors; electric breakdown of solids; integrated circuit technology; leakage currents; permittivity; strontium compounds; 256 Mbit; Ba/sub x/Sr/sub 1-x/TiO/sub 3/; DRAM cells; Pt-Ta capacitor electrode; TDDB; equivalent SiO/sub 2/ thickness; high-dielectric-constant material; leakage current; reliability; stacked DRAM capacitor; time-dependent dielectric breakdown; unit area capacitance; Capacitors; Dielectric constant; Dry etching; Electrodes; Leakage current; Material storage; National electric code; Random access memory; Semiconductor films; Strontium;
Conference_Titel :
Electron Devices Meeting, 1991. IEDM '91. Technical Digest., International
Conference_Location :
Washington, DC, USA
Print_ISBN :
0-7803-0243-5
DOI :
10.1109/IEDM.1991.235298
