| 摘要 |
PURPOSE:To prevent a decrease in pressure resistance of a semiconductor device, by increasing the concentration of impurity in a p-type base layer, whereby a n-type channel can be prevented from being formed in the interface between the base layer and an element isolation insulating layer. CONSTITUTION:A field oxide film 2 is provided on a n-type Si 1, and a Si3N4 film 11 and a SiO2 film 12 are laminated on the film 2. The films 11, 12 are partially removed by etching such that the remainder of the films 11, 12 are extended over the surface of an end portion of the oxide film 2 which is one of the above-mentioned oxide films. At this time, the SiO2 film 12 is etched a little excessively to make it smaller than the Si3N4 film so that the films 11, 12 are in a stepped arrangement. B ions are then injected to form a p-type base layer 4. As a result, a three-step base- collector junction 14 is formed, which has a base layer 4' extended deep under the isolated layer 2. The films 11, 12 are then removed and a SiO2 film 15 is formed. An opening is made in the film 15 to inject B ions thereinto. As a result, an emitter layer 3 is formed, in which a predetermined maximum value of distribution of concentration is in the vicinity of an emitter-base junction 16, so that an inversion channel is not formed in an interface 5 between the layer 3 and the isolated layer 2. Accordingly, the pressure resistance between the collector and emitter. Finally openings are made in the film 15, and electrodes 8, 8' are set therein to complete a semiconductor device.
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