Enhancement of Data Retention Time for 512-Mb DRAMs Using High-Pressure Deuterium Annealing

We have investigated the effect of high-pressure deuterium annealing (HPDA) for retention time improvement of 512-Mb dynamic random access memories with 3D cell transistors. Compared with a control sample annealed in a conventional forming gas (4% H
₂
/N
₂
), additional annealing in a high-pressure deuterium ambient (100% D
₂
) at 400degC for 30 min improved the data retention time. This improvement can be explained by the decrease of junction leakage currents due to D
₂
incorporation at the SiO
₂
/Si interface near trench isolation region. In addition, HPDA introduced during postmetal anneal exhibited improved hot carrier reliability.