US Patent 7589551 On-wafer AC stress test circuit

To make an alternating current (AC) stress test easier to perform in a wafer, an AC stress test circuit for performing the AC stress test on a test device fabricated in a test region of the wafer includes an oscillator module fabricated in the test region, a diode module fabricated in the test region coupled to an output of the oscillator module, and a select transistor fabricated in the test region having a gate terminal coupled to an output of the diode module, a second terminal coupled to a gate of the test device, and a third terminal coupled to a test voltage source.