Improvement of the tail component in retention time distribution using buffered n-implantation with tilt and rotation (BNITR) for 0.2 um DRAM cell and beyond

The novel junction process scheme in DRAM memory cell with 0.2 um design rule and STI (Shallow Trench Isolation) has been investigated to improve the tail component of DRAM retention time distribution. In this paper, we propose BNITR (Buffered N-Implantation with Tilt and Rotation) process scheme that is designed on the basis of the local field-enhancement model of the tail component and report an excellent improvement effect in tail distribution of retention time without device degradation.