An IGBT includes a floating P well, and a floating N+ well that extends down into the floating P well. A bottom surface of the floating P well has a waved contour so that it has thinner portions and thicker portions. When the device is on, electrons flow laterally from an N+ emitter, and through a first channel region. Some electrons pass downward, but others pass laterally through the floating N+ well to a local bipolar transistor located at a thinner portion of the floating P type well. The transistor injects electrons down into the N− drift layer. Other electrons pass farther through the floating N+ well, through the second channel region, and to an electron injector portion of the N− drift layer. The extra electron injection afforded by the floating well structures reduces VCE(SAT). The waved contour is made without adding any masking step to the IGBT manufacturing process.