Reverse conducting igbt

Abstract

An insulated gate bipolar transistor (IGBT) is provided comprising a semiconductor substrate having the following regions in sequence: (i) a first region of a first conductive type having opposing surfaces, a column region of a second conductive type within the first region extending from a first of said opposing surfaces; (ii) a drift region of the second conductive type; (iii) a second region of the first conductive type, and (iv) a third region of the second conductive type. There is provided a gate electrode disposed to form a channel between the third region and the drift region, a first electrode operatively connected to the second region and the third region, a second electrode operatively connected to the first region and the column region. The arrangement of the IGBT is such that the column region is spaced from a second surface of the opposing surfaces of the first region, whereby a forward conduction path extends sequentially through the third region, the second region, the drift region, and the first region, and whereby a reverse conduction path extends sequentially through the second region, the drift region, the first region and the column region. Reverse conduction of the IGBT occurs through a thyristor structure which is embedded in the IGBT. Such an IGBT structure is advantageous over a reverse conducting IGBT structure in which an anti-parallel diode is integrated or embedded because it provides improved reverse conduction and snapback performance.