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Gettering Utilizing Implant Damage and Highly Disordered Epitaxial Layer

IP.com Disclosure Number: IPCOM000086872D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 97K

Publishing Venue

IBM

Related People

Poponiak, MR: AUTHOR [+2]

Abstract

A large portion of nonactive device areas of the wafer is used for the gettering purpose. This implanted area is also used to prevent the nucleation sites for creating epitaxial (epi) stacking faults.

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Gettering Utilizing Implant Damage and Highly Disordered Epitaxial Layer

A large portion of nonactive device areas of the wafer is used for the gettering purpose. This implanted area is also used to prevent the nucleation sites for creating epitaxial (epi) stacking faults.

The process uses standard bipolar processing up to and including subcollector and first isolation diffusions and drive-ins. A block-out mask 5 of photoresist or polyimide at least 0.2 mil larger than the isolation device area is used (Fig. 1). This gives a safety factor of 2.5 mu m spacing from any epitaxial stacking fault, which can be nucleated at the edge of the implant damage closest to the active device 6.

Argon (or other suitable ion such as boron, silicon, nitrogen, arsenic, phosphorus and neon can be implanted depending on specific devices or applications) is implanted with a typical energy of 25-200 Kev and dose of 10/14/- 10/16/. These energies and doses can create defect densities in the epi of 10/4/- 10/8//cm/2/, as shown by arrows 7, to form the damage in the unexposed silicon surface 8.

The masking material and initial oxides are removed to produce the Fig. 2 structure. The wafers are now put into an epi system, either RF or a radiant- heated type. A typical heat cycle prior to actual epi deposition is: room temperature to 900 degrees C, 2-3 min.; 900 degrees C, 6 min.; 900 degrees to 1150 degrees C, 2 min.; 1150 degrees C, 10 min.; then epi deposition (21 min. at high temperature prior to epi deposition). This time and temperature is adequate to getter fast moving metals such as copper and nickel to the implant damage regions. Slo...