The present disclosure provides integrated circuit (IC) devices and repair methods of the IC devices. An IC device includes a PMOS transistor including a substrate, a gate dielectric layer on the substrate, and a gate on the gate dielectric layer. The IC device also includes a repair circuit configured to apply a negative bias voltage to the substrate of the PMOS transistor, when the PMOS transistor is in an OFF state, to cause injections of electrons in the substrate into the gate dielectric layer to neutralize holes caused by negative bias temperature instability (NBTI) effect. The repair circuit is further configured to stop applying the negative bias voltage to the substrate of the PMOS transistor when the PMOS transistor is in an ON state. As such, the disclosed IC device repairs defect caused by NBTI effect in the PMOS transistor and prolongs the lifespan of the PMOS transistor.