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Bipolar Structure with Junction Capacitance Integrated within Each Cell

IP.com Disclosure Number: IPCOM000053110D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Abbas, SA: AUTHOR [+3]

Abstract

In future bipolar circuits with extremely fast switching speeds there is a need to provide for decoupling and speed-up capacitors within each cell to permit the circuit to switch as fast as possible without causing excessive noise due to capacitive/inductive couplings to the neighboring circuits. This would reduce the system delay that would be involved in transporting signals in and out of the integrated circuit chips.

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Bipolar Structure with Junction Capacitance Integrated within Each Cell

In future bipolar circuits with extremely fast switching speeds there is a need to provide for decoupling and speed-up capacitors within each cell to permit the circuit to switch as fast as possible without causing excessive noise due to capacitive/inductive couplings to the neighboring circuits. This would reduce the system delay that would be involved in transporting signals in and out of the integrated circuit chips.

A structure and a process which allows the formation of capacitors integrated within each cell on a chip are described. The structure consists of a P(+) substrate 10 over which a P(-) epitaxial layer 11 is grown. Arsenic implant or diffusion is made into the P(-) epitaxial layer 11 to form a blanket N(+0 layer 12 which will be used eventually as the subcollector. A silicon dioxide layer 13 is formed at the top during the drive-in cycle. Using a mask to delineate the P resistor beds (and possibly to delineate NPN emitter follower devices), areas are opened in the silicon dioxide layer 13 and deep phosphorous implant is made through these openings, as shown in Fig. 1. The depth of the implant is adjusted such that the boron from the P substrate 10 and phosphorous from the N implant do not overlap at this stage, but are kept apart during the subsequent N(-) epitaxial deposition 15 and other hot processes until the last thermal cycle, usually the emitter drive-in, is completed. During this emitter drive-in, these N(+) and P(+) regions are caus...