Browse Prior Art Database

Polysilicon Base/Emitter Contact Process

IP.com Disclosure Number: IPCOM000046219D
Original Publication Date: 1983-Jun-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 75K

Publishing Venue

IBM

Related People

Barbee, SG: AUTHOR [+2]

Abstract

The above drawings illustrate the processing stages utilizing oxidized polysilicon as the dielectric separating an emitter contact metal interconnection and doped polysilicon base contact interconnection.

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Polysilicon Base/Emitter Contact Process

The above drawings illustrate the processing stages utilizing oxidized polysilicon as the dielectric separating an emitter contact metal interconnection and doped polysilicon base contact interconnection.

The substrate, as shown in Fig. 1, is processed in accordance with the following steps: 1. Polysilicon deposition (Poly I) 2. Polysilicon oxidation

3. Dopant implant

4. Si3N4 (chemical vapor deposition)

In the next step (Fig. 2), a polysilicon mask is formed by an RIE (reactive ion etch) of the polysilicon followed by chemical vapor deposition (CVD) of SiO2 . This is followed by a chemical vapor deposited Si3N4 layer, and an implanted base (Fig. 3).

Fig. 4 shows a suceeding polysilicon deposition (Poly II), with (Fig. 5) a blanket reactive ion etching of the silicon.

Following the RIE of the Poly II layer, the remaining polysilicon is oxidized while all active device areas are protected with the Si3N4 to prevent oxidation of any of the contact areas. The resultant structure is shown in Fig. 6.

The emitter contact is now opened by reactive ion etching of the thin Si3N4 and the CVD SiO2 film in all the contact areas, as shown in Fig. 7. Fabrication of an ion-implanted emitter is then completed with anneal and P contacts opened to complete the structure shown in Fig. 8.

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