Self-Aligned Local Channel Implantation Using Reverse Gate Pattern for Deep Submicron Dynamic Random Access Memory Cell Transistors

Abstract

In this paper, we propose the highly manufacturable self-aligned local channel implant (SALCI) cell structure for dynamic random access memory of 4 Gb and larger. For conventional cell transistors, data retention degradation caused by the junction leakage current and capacitance become unavoidable as the gate length is scaled down, due to the highly doped channel. In order to achieve more enhanced and reliable performance under low-voltage operation, decreasing substrate doping beneath the source/drain junction while maintaining high substrate doping at the channel region by means of the self-aligned local channel implant without additional photomask steps will be very useful.