The capabilities of photon emission microscopy with CCD and MCT camera systems for the 90 nm CMOS technology node were investigated. This was done with a dedicated test circuit with selectable shorts with resistance between 0 to 40 kΩ. Our investigations showed that conventional PEM with CCD systems is not possible anymore due to the reduction in photon emission intensity in the visible range. However, photon emission can be enhanced by using elevated supply voltages. For these overdrive conditions PEM with a CCD system is still feasible. We furthermore show that PEM is in principle capable of determining the state of a circuit and that PEM in combination with defect simulations can determine defect characteristics. In this manner, for example, the resistance of a short can be estimated by localising the PMOST emission spot.