Abstract A three dimensional (3-D) photon emission failure analysis method has been developed to pinpoint failure sites or emission sites on the x, y, and z planes of a degraded diode. The 3-D analysis consists of a cross-sectioning step process on two adjacent sides of a diode utilizing two photon emission sites from respective sides of the die as a map. This process negates the uncertainty and long processing times during cross-sectional analysis to find minute defects in diodes.