We did lose something when we moved to FinFET. In planar devices, the width of the transistor is lithographically defined, so it is a highly flexible parameter. But in FinFETs, transistor widths come in discrete increments—adding one fin at a time—a feature often referred to as fin quantization. Although FinFETs can be flexible, fin quantization remains an important design constraint. The design rules surrounding it and the desire to add more fins to improve performance increase the overall area of the logic cell and complicate the interconnect stack that turns a single transistor into a complete logic circuit. It also increases the capacitance of the transistor, which slows down some of its switching speed. So, while FinFET has served us well as an industry workhorse, a new, more refined approach is still needed.
In RibbonFETs, the gate surrounds the transistor channel region for enhanced charge carrier control. The new structure also enables better performance and finer optimizations.