Temperature dependence of latch-up characteristics in LDD CMOS devices

The incremental rate of the latch-up holding current (Ih) with decreasing temperature is larger in the bulk substrate than in the epitaxial substrate. The substrate dependence is mainly due to the difference in the temperature coefficients of the material resistivity. Although Ihincreases significantly with decreasing temperature, the latch-up triggering voltage (Vtrig) in an inverter remains relatively constant, posing a limit for VLSI device miniaturization at low temperatures.