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Ion Implanted Emitter Process in Silicon Nitride Silicon Dioxide Passivation Technology

IP.com Disclosure Number: IPCOM000084457D
Original Publication Date: 1975-Nov-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Bratter, RL: AUTHOR [+2]

Abstract

In the formation of ion-implanted emitters in fabrication of integrated circuits utilizing a silicon nitride/silicon dioxide passivation technology, a problem is often encountered in ensuring that subsequently formed metallic contacts to the emitter do not extend to or beyond the lateral base-emitter junction, to thus short-out this junction and render the transistor ineffective.

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Ion Implanted Emitter Process in Silicon Nitride Silicon Dioxide Passivation Technology

In the formation of ion-implanted emitters in fabrication of integrated circuits utilizing a silicon nitride/silicon dioxide passivation technology, a problem is often encountered in ensuring that subsequently formed metallic contacts to the emitter do not extend to or beyond the lateral base-emitter junction, to thus short- out this junction and render the transistor ineffective.

With reference to Fig. 1, there is shown an integrated circuit at a fabrication stage prior to emitter formation. P base 10 is formed in epitaxial layer 11. The masking or passivation structure comprises bottom silicon dioxide layer 12 and top silicon nitride layer 13, through which emitter-defining opening 15 passes. A very thin layer 16 of silicon dioxide has been formed in emitter opening 15 to serve as an ion-implantation shield.

It should be noted that when utilizing standard integrated circuit fabrication techniques for forming opening 15, silicon nitride layer 13 overhangs the opening through silicon dioxide layer 12, thereby leaving a relatively narrow width, W, which will be the effective width through which the ion implantation can be made, since silicon nitride 13 will block the ions during the subsequent ion implantation Step to form the emitter. Thus, when conventional ion implantation utilizing either arsenic or phosphorous to form N emitter 17 (shown in dotted lines) is utilized, the b...