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Compensating for the Depletion of Boron Produced in NPN Bipolar Transistors

IP.com Disclosure Number: IPCOM000077584D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Crowder, BL: AUTHOR [+2]

Abstract

During the manufacture of an NPN bipolar transistor, arsenic is diffused into the emitter. As a consequence of such diffusion, boron is severely depleted in the base region adjacent the emitter (see the figure showing a plot of concentration of boron versus depth).

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Compensating for the Depletion of Boron Produced in NPN Bipolar Transistors

During the manufacture of an NPN bipolar transistor, arsenic is diffused into the emitter. As a consequence of such diffusion, boron is severely depleted in the base region adjacent the emitter (see the figure showing a plot of concentration of boron versus depth).

To compensate for such depletion, boron is ion implanted, through the emitter hole after arsenic diffusion has taken place, in the base region. In this manner, the boron profile can be tailored at the vicinity of the boron-depleted area. Subsequent low-temperature (e.g., 850 degrees C for 30 minutes) annealing renders the boron electrically active without altering other diffusion profiles in the NPN transistor.

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