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Method for buried poly-silicon gettering on layer transfer SOI wafers

IP.com Disclosure Number: IPCOM000032362D
Publication Date: 2004-Nov-02
Document File: 3 page(s) / 83K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for buried poly-silicon gettering on layer transfer silicon-on-insulator (SOI) wafers. Benefits include improved functionality, improved performance, and improved yield.

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Method for buried poly-silicon gettering on layer transfer SOI wafers

Disclosed is a method for buried poly-silicon gettering on layer transfer silicon-on-insulator (SOI) wafers. Benefits include improved functionality, improved performance, and improved yield.

Background

              Conventionally, SOI wafers manufactured by the layer transfer method do not have an effective means of intrinsic gettering for metallic impurities. The thin SOI wafers are prone to metallic contamination during wafer manufacturing or during device processing. Gettering is the trapping and neutralization of unwanted elements.

General description

              The disclosed method uses the gettering capability of poly-silicon with SOI layer transfer. The buried poly-silicon layer is very effective in trapping metallic impurities such as copper (Cu), nickel (Ni), and iron (Fe), which can degrade the device performance and yield if no gettering layer is present.

              The key elements of the method include:

•             Deposition of 10 to 20 nm of poly-silicon using a standard low-pressure chemical vapor deposition (CVD) process on the handle wafer. This poly-silicon layer acts as a very efficient gettering site for removing metallic impurities.

•             Donor wafer with a specific oxide thickness for becoming the buried oxide (BOX) for the final SOI wafer. The donor wafer receives an H2 implant for layer transfer.

•             Layer transfer by wafer bonding of donor wafer (upside down) on th...