SSVT (six stacked vertical transistors) SRAM cell architecture introduction: design and process challenges assessment

This paper presents a new design architecture for advanced logic SRAM cells using six vertical transistors (with carrier transport along the Z direction), stacked one on top of each other. Virtual fabrication technology was used to identify different process integration schemes to enable the fabrication of this architecture with a competitive XY footprint at an advanced logic node: a unit cell area of 0.0093 um2 was demonstrated in this work. This study illustrates that virtual fabrication can be a key enabling element for technology pathfinding, and that it can be used to identify expected module development challenges prior to tape-out or wafer processing.