Understanding Distance-Dependent Variations for Analog Circuits in a FinFET Technology

Analog circuits are sensitive to device variations. Random device variations are well modeled and quantified in the literature, but analog-relevant distance-dependent device variation measurements have not been reported for newer technology nodes. To reduce the impact of distance-dependent variations, layout patterns such as common-centroid are often used. However, these patterns use larger area and have higher parasitics than clustered (NonCC) patterns in FinFET technologies where unit parasitics are higher and design rules are more complex. This work measures variations on multiple dies in a 12nm FinFET technology, each with about 10,000 devices, and models the distance-dependent component. We then apply these findings to show that NonCC patterns can be used in lower-resolution DACs to meet mismatch specifications while reducing layout area.