Insulated gate bipolar transistor

摘要

An IGBT includes a plurality of n⁺ doped regions ( 11 ) selectively formed in a main surface ( 103 ) of a p⁺ semiconductor layer ( 12 ) opposite from an n type semiconductor layer ( 80 ) without being connected to the n type semiconductor layer ( 80 ). The n⁺ doped regions ( 11 ) are formed in corresponding relation to and only under channel regions (CH 1 a-CH 1 d) of structures ( 200 a- 200 d), respectively. This lowers the effective concentration of the p⁺ semiconductor layer ( 12 ) on the n⁺ doped regions ( 11 ) to reduce the number of holes injected from a collector layer ( 9 ) in an off state, reducing a leakage current.