Patent ID: 9601592
Date: 2017-03-21
CPC Classifications: H01L

Claim:
1. A method of manufacturing an IGBT, comprising: forming an n-type emitter region in a range to be exposed to an upper face of a semiconductor substrate, the emitter region having a depth; forming a p-type top body region below the depth of the emitter region by implanting p-type impurities into the upper face of the semiconductor substrate such that the p-type impurities stop within the depth of the emitter region, and diffusing the implanted p-type impurities, the top body region having a depth; forming an n-type floating region below the depth of the top body region by implanting n-type impurities into the upper face of the semiconductor substrate such that the n-type impurities stop within the depth of the emitter region, and diffusing the implanted n-type impurities, the floating region having a depth; forming a trench in the upper face of the semiconductor substrate, and forming a gate insulating film that covers an inner face of the trench, and a gate electrode that is arranged in the trench; and forming a p-type bottom body region below the depth of the floating region by implanting p-type impurities into the upper face of the semiconductor substrate such that the p-type impurities stop at a depth below the floating region, after forming the trench, the gate insulating film, and the gate electrode, wherein in the forming of the trench, the trench is arranged so that, after the respective formings are carried out, the trench penetrates the emitter region, the top body region, the floating region, and the bottom body region, and when a distribution of a concentration of p-type impurities in the top body region and the floating region, which are located below the emitter region, is viewed along a thickness direction of the semiconductor substrate, the concentration of the p-type impurities decreases as a downward distance increases from an upper end of the top body region that is located below the emitter region, and reaches a local minimum value at a predetermined depth in the floating region.