For sub-5nm technology nodes, gate-all-around (GAA) FETs are positioned to replace FinFETs to enable the continued miniaturization of ICs in the future. In this paper, we introduce SkyBridge-3D-CMOS 2.0, a 3D-IC technology featuring integration of stacked vertical GAAFETs and 3D interconnects. It aims to provide an integrated solution to critical technology aspects, especially when scaling to sub-5nm nodes. We address important aspects such as 3D fabric components, CAD tool flow, compact model for the GAAFETs and a scalable manufacturing process.
Conventional 2D CMOS faces severe challenges sub-22nm nodes. The monolithic 3D (M3D) IC technology enables ultra-high density vertical connections and provides a good path for technology node scaling. Transistor-level (TR-L) monolithic 3D IC is the most advanced and fine-grained M3D IC technology. In this paper, for the first time, the detailed design as well as benefits and challenges of a silicon validated 14nm Finfet process design kit (PDK) based TR-L M3D IC technology is explored. TR-L M3D standard cell layout is achieved based on 14nm Finfet design rules and feature sizes.
Parallel and monolithic 3D integration directions offer pathways to realize 3D integrated circuits (ICs) but still lead to layer-by-layer implementations, each functional layer being composed in 2D first. This mindset causes challenging connectivity, routing and layer alignment between layers when connected in 3D, with a routing access that can be even worse than 2D CMOS, which fundamentally limits their potential.
As technology scales, more sophisticated fabrication processes cause variations in many different parameters in the device. These variations could severely affect the performance of processors by making the latency of circuits less predictable and thus requiring conservative design approaches. In this paper, we use Monte-Carlo simulations in addition to worst-case circuit analysis to establish the overall delay due to process variations in a cache subsystem under both typical and worst-case conditions.
A new hybrid CMOS-nanoscale circuit style has been developed that uses only one type of Field Effect Transistor (FET) in the logic portions of a design. This is enabled by CMOS providing control signals that coordinate the operation of the logic implemented in the nanoscale. In this paper, the new circuit style is explored, examples from a microprocessor design are shown, manufacturing and density implications discussed.