| 摘要 |
<p>Semiconductor device comprising a lateral bipolar transistor, for example of the PNP type, having, in an N epitaxial layer (3) formed on the surface of a P substrate (1), a P emitter region (15,16) and a P collector region (17), spaced laterally by an N base region (19), this transistor further comprising a N<++> buried layer (18). In this lateral transistor, the current gain is very greatly increased, when the emitter is formed by a said first, lightly P-doped, partial emitter region, extending under an insulating layer (6), and a said second, heavily P<++>-doped, partial emitter region (16), extending under the emitter contact area (26) delimited by an opening in the insulating layer (6). The respective dopings and the thicknesses of the first (15) and the second (16) emitter regions are provided so that the first region is transparent to the electrons and the second forms a screen for the electrons. Moreover, the ratio of the areas of the two partial regions (Sox/Sm) is greater than 2, the area (Sm) of the second region (16) being chosen to be small. The various regions of the transistor are formed by very thin layers. The transistor may also be NPN. <IMAGE></p> |
