A self-aligned latch-free IGBT with sidewall diffused n/sup +/ emitter

A self-aligned latch-free IGBT, where a trench is located in the middle of p/sup -/ body, has been proposed and verified by process and device simulations. No additional mask steps for n/sup +/ source, p/sup ++/ region and source contact are required so that small size body would be obtained. As the n/sup +/ source is formed by impurity diffused through the sidewall of the trench in the middle of the body, high latch-up capability may be achieved due to the small body resistance and low emitter efficiency of the parasitic n-p-n transistor. Latch-up current densities higher than 10000 A/cm/sup 2/ have been achieved by adjusting the process conditions.