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Browse Prior Art Database

Process for Making Sidewall Resistors With Single Crystal Contacts

IP.com Disclosure Number: IPCOM000046399D
Original Publication Date: 1983-Jul-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Bhatia, HS: AUTHOR [+3]

Abstract

Polysilicon high value resistors are made using a reactive ion etch (RIE)-sidewall technique that provides for single crystal or polycrystalline contact to the sidewall resistors.

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Process for Making Sidewall Resistors With Single Crystal Contacts

Polysilicon high value resistors are made using a reactive ion etch (RIE)- sidewall technique that provides for single crystal or polycrystalline contact to the sidewall resistors.

Starting with the structure of Fig. 1, (1) form insulator 2 layer of SiO2 (4000), and (2) etch rectangular windows in insulator 2 using a mask. This typically would be a minimum line width etch.
(3) Deposit 3000 doped poly and blanket RIE to form sidewalls. These sidewall rails (cross-hatched in Fig. 2) are the body of the resistor. In this implementation, the regions where the rails contact the single crystal silicon form the contacts to the resistor.

The single crystal contact regions could have been previously doped by diffusion or ion implantation, or could be implanted later. Typically, this region is of low sheet resistance. See Fig. 2. (4) Thermally oxidize the structure (500). (5) Etch contact holes to the single crystal regions and make conventional contacts, as shown in Fig. 3.

Alternatively, contact can be made to the sidewall resistors via a polycrystalline layer.

(l) Oxidize the substrate of Fig. 4 (500) followed by appropriate CVD (chemical vapor deposited) oxide (3000-5000 ). (2) Deposit 2000-4000 of P doped poly. (3) Deposit CVD oxide 500-1000. (This oxide is for photoresist adhesion. It is not needed if good resist-poly adhesion is obtained.) (4) Using a mask, etch through the layers to produce poly pad...