Fingered Transistors
Fingers involve splitting a single large transistor into multiple smaller transistors (or “fingers”) and connecting them in parallel.
Instead of having one large transistor, the width is divided into several parts.
Each finger shares a common gate but has separate source and drain regions.
The Bulk/Substrate contact is a ring, also known as a guard ring. The reason making the bulk contact surround the transistor, has been nicely elaborated by Gemini[1][2].

- ↑ Analysis: Single Bulk Contact vs. Bulk Contact Ring for a FET
- ↑ Expert Assessment on Bulk Contact Geometry for Multi-Fingered MOSFET P-Cells in LibrePDK