Title :
Comparison of DRAM capacitor dielectric by stored charge and holding time using TQV chart
Author_Institution :
Fujitsu Ltd., Kawasaki, Japan
Abstract :
Dielectric films for DRAM storage capacitors were examined using a TQV chart. This chart enables comparison of performance between different insulating materials with different current-voltage behaviors. It was believed that insulators with higher dielectric constant have larger leakage current, but the results show otherwise. A BaSrTiO/sub 3/ film performed best, but the step coverage of the film should be improved. Silicon nitride films are approaching a thickness limitation, but could be effective if the capacitor electrode structure is improved to utilize the good step coverage.<>
Keywords :
DRAM chips; capacitors; dielectric thin films; insulation testing; leakage currents; permittivity; BaSrTiO/sub 3/ film; DRAM capacitor dielectric; Si/sub 3/N/sub 4/ films; TQV chart; Ta/sub 2/O/sub 5/ films; capacitor electrode structure; current-voltage behaviors; dielectric constant; holding time; insulating materials; leakage current; step coverage; stored charge; Capacitors; Dielectric films; Dielectric materials; Dielectrics and electrical insulation; Electrodes; High-K gate dielectrics; Leakage current; Random access memory; Semiconductor films; Silicon;
Journal_Title :
Electron Device Letters, IEEE
