Bipolar transistor and method of manufacturing the same.

摘要

A first device region (10) of one conductivity type adjacent one major surface (1a) of a semiconductor body (1) has a relatively highly doped subsidiary region (11) spaced from the one major surface (1a) by a relatively lowly doped subsidiary region (12). A second device region (20) of the opposite conductivity type within the subsidiary region (12) has an intrinsic subsidiary region (21) and an extrinsic subsidiary region (23,24) surrounding the intrinsic subsidiary region (21) forming respective first and second pn junctions (22,25) with the relatively lowly doped subsidiary region (12). A third device region (30) of the one conductivity type is formed within the intrinsic subsidiary region (21) surface (1a). An additional region (60,60 min ,61,62) is provided beneath the extrinsic subsidiary region (23,24) so as to lie within the spread of the depletion region (250) associated with the second pn junction (25) when the first and second pn junctions (22,25) are reverse-biassed thereby extending the depletion region (250) beneath the emitter region (30) to cause an increase in the Early voltage (Veaf) of the device.