A method comprising applying a first voltage to a first transistor to create a defect in the first transistor, wherein (i) the first voltage is greater than a maximum operational voltage of the first transistor and (ii) the maximum operational voltage does not cause a defect in the first transistor when applied to the first transistor. The method further includes determining whether the first transistor has been programmed, including (i) measuring a first current through the first transistor, (ii) measuring a second current through a second transistor, and (iii) comparing the measured first current to the measured second current, wherein a difference between the measured first current and the measured second current indicates that the first transistor has been programmed.