Reconfigurable delay cell for area-efficient implementation of on-chip MOSFET monitor schemes

To measure target MOSFET variation, specific monitor schemes are required. With device scaling, developing each monitor scheme is costly. This paper proposes a universal delay monitor cell which enables measurements of various types of variations with single monitor scheme. The monitor cell is reconfigurable and standard cell compatible; thus it can be used in the conventional place and route flow. An area-efficient monitor scheme to monitor global, local, and dynamic variations is developed. Measurement results from a 65-nm test chip shows the validity of the proposed monitor cell. The proposed cell enables area-efficient and low cost implementation of monitor schemes which can be integrated with application such as testing and adaptive voltage scaling.