Discrimination of parasitic bipolar operating modes in ICs with emission microscopy

The characterization of bipolar device operation modes by emission microscopy is discussed. In order to separate different radiation mechanisms, diode and parasitic bipolar n-MOS transistor test structures have been investigated at different temperatures and operating modes. Since it is extremely sensitive to the high energy branch of the radiation, the S25 photocathode of an image intensifier enables a distinction to be made, by means of temperature variation between forward and reverse operation, diffusion, and field current. This measuring technique allows latch-up to be identified as a diffusion-controlled phenomenon.<<ETX>>