Designing and Benchmarking of Double-Row Height Standard Cells

This article presents our experience of designing double-row height standard cell libraries and their use for chip designs. Seven cell libraries are designed based on the 15nm process technology stipulated in FreePDK15. A single-row height of 7.5 M2 tracks is used as a basis for designing double-row height cells. Two minimum-sized transistors, one having two fins and the other having four fins, are employed to design 1X drive-strength cells. Among the seven libraries, two libraries consist of only single-row height cells. The other five libraries each consist of partly single-row height cells and double-row height cells. Our experiments show that a double-row height library can achieve on average -2% to 21% area saving and -23% to 19% smaller power-delay-area product. Our results also show that using a large minimum-sized transistor for designing a double-row height library is not viable if extensive transistor folding is required.