A 65 nm Complementary Metal--Oxide--Semiconductor 400 ns Measurement Delay Negative-Bias-Temperature-Instability Recovery Sensor with Minimum Assist Circuit

概要

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We propose a negative bias temperature instability (NBTI) recovery sensor with a 400 ns measurement delay. The measurement delay is about 30 ms when the leakage current of a small single transistor is measured by the conventional method. This sensor contains many unit cells. One unit cell includes 10 p-channel metal--oxide--semiconductor (PMOS) Device-under-tests (DUTs) and two assist n-channel metal--oxide--semiconductor (NMOS) devices. Parallelizing many unit cells can amplify the leakage current and the assist circuit can reduce the rush current to the ammeter, which keeps the measurement range of the ammeter constant during measurement. A short measurement delay is achieved by these two factors. It is confirmed that from 50 to 125 °C, NBTI recovery follows $\log t$ from 400 ns to 3000 s. By stressing and recovering thousands of PMOS transistors at the same time, we can observe that the time constants of positively charged defects, which are related to NBTI, are log-uniformly distributed in the PMOS devices. Also, this circuit has the highest fidelity to NBTI recovery measurement because off-leak current is used for NBTI recovery characterization and stress is not added during measurement.
2011-04-25