| 摘要 |
A method and test circuit provide measurements to aid in the understanding of time-varying threshold voltage changes such as negative bias temperature instability and positive bias temperature instability. In order to provide accurate measurements during an early stage in the threshold variation, a current generating circuit is integrated on a substrate with the device under test, which may be a device selected from among an array of devices. The current generating circuit may be a current mirror that responds to an externally-supplied current provided by a test system. A voltage source circuit may be included to hold the drain-source voltage of the transistor constant, although not required. A stress is applied prior to the measurement phase, which may include a controllable relaxation period after the stress is removed.
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