An insulated gate bipolar transistor comprises a drain which supports a highly doped p-type substrate layer; a low doped n-type drift layer supported over the substrate layer; a base layer supported over the drift layer including a trench extending into the base layer, and supporting an insulated gate on an upper surface thereof separated from the trench by a highly doped n-type source region, the trench having a highly doped p-type layer at the bottom thereof vertically separated from the source region; and a source layer disposed over the n-type source region and extending into the trench covering the highly doped p-type layer in the trench bottom, wherein an applied voltage to the gate forms a conducting inversion channel in the base layer for electron transport from the source region to the drain, and the highly doped p-type layer in the bottom of the trench collects holes injected from the substrate layer into the drift layer thereby improving latch up immunity for the transistor.