Title :
Ultrathin oxide-nitride dielectrics for rugged stacked DRAM capacitors
Author :
Fazan, Pierre C. ; Mathews, Viju K. ; Chan, Hiang C. ; Ditali, Akram
Author_Institution :
Micron Technol. Inc., Boise, ID, USA
Abstract :
Ultrathin dielectric materials that provide high capacitance values are needed for 64- and 256-Mb stacked DRAMs. It is shown that capacitance values as high as 12.3 fF/ mu m/sup 2/ can be obtained with ultrathin nitride-based layers deposited on rugged polysilicon storage electrodes. These films present the reliability and low leakage current levels required for 3.3-V applications. The nitride thickness, however, cannot be scaled much below 6 nm to avoid the oxidation-punchthrough mechanisms that appear when too-thin films are unable to withstand the reoxidation step.<>
Keywords :
DRAM chips; MOS integrated circuits; capacitors; dielectric thin films; leakage currents; semiconductor-insulator boundaries; 12.3 fF; 256 Mbit; 256-Mb; 3.3 V; 6 nm; 64 Mbit; Si; Si/sub 3/N/sub 4/; SiO/sub 2/; low leakage current; oxide-nitride dielectrics; reliability; rugged polysilicon storage electrodes; stacked DRAM capacitors; ultrathin dielectric materials; ultrathin nitride-based layers; Capacitance; Capacitors; Degradation; Dielectric materials; Dielectric thin films; Electrodes; Leakage current; Manufacturing; Material storage; Random access memory;
Journal_Title :
Electron Device Letters, IEEE
