On-Chip Monitoring of Time-Dependent Dielectric Breakdown (TDDB) using a Novel Leakage Current Sensor with Digital Output

The reliability of integrated circuits is threatened by aging-related effects like Time Dependent Dielectric Breakdown (TDDB). This is especially important in safety-critical high-volume long-lifetime applications like automotive and medicine. To address this challenge, on-chip monitoring and fast characterization of these aging phenomena are becoming increasingly important. This paper demonstrates a novel leakage current sensor with a digital output designed to provide an efficient and reliable means of monitoring TDDB. The low-voltage design of this monitor eliminates the requirement for an on-chip charge pump for the sensing circuit and reduces power consumption. The leakage current sensing range of the monitor is from 10pA to 5μA and requires only a few clock cycles of measurement time for most of the lifetime of the device under test and has been demonstrated to be fast, efficient, and effective for on-chip monitoring and characterization of TDDB. Using Cadence Spectre/AMS simulations, this small-area monitor has been validated to be a fast and reliable device for monitoring the gate leakage current of MOS devices and capacitors.