The Effect of Reduced Gate Leakage on Improved Retention Time of Metal-Ferroelectric (PbZr_(0.53)Ti_(0.47)O_3)-Insulator (ZrO_2)-Semiconductor Capacitors

摘要

Al/ Pb (Zr_(0.53), Ti_(0.47)) O_3 (PZT) /ZrO_2/Si metal-ferroelectric-insulator semiconductor (MFIS) capacitors were fabricated. The wafers were given a H_2O_2 pre-treatment before ZrO_2 deposition and a HC1 treatment after deposition. The interface states were reduced from 5.62 x 10~(13)/cm~2 to 4.0 x 10~(12)/cm~2 and the composite dielectric constant of ZrO_2 film plus interfacial layer was increased from 5.54 to 7.3. The leakage current density was 5.4 x 10~(-6) A/cm~2 at a sweep voltage of 5 V. The retention time of Al/PZT/ZrO_2/Si capacitors after these surface treatments was increased from 13.3 hours to 17.1 days. The improved retention time is attributed to the reduced gate leakage current.