Temperature and Epi Thickness Dependence of the Heavy Ion Induced Latchup Threshold for a CMOS/EPI 16K Static RAM

Data have been obtained with krypton and xenon ions for the latchup threshold vs. temperature of four different versions of a Harris CMOS/epi 16K static RAM. These special versions of the HM6516 RAM have 12-micron, 9-micron, 7-micron and 5-micron epi thicknesses, as grown. The test data showed a marked improvement in latchup resistance with decreasing epi thickness and with decreasing temperature over the range of 25°C (operating chip ambient) to 100°C.