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New Spacer Scheme to Resolve the Gate to Epi Short Issue

IP.com Disclosure Number: IPCOM000236151D
Publication Date: 2014-Apr-09
Document File: 2 page(s) / 45K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a new spacer scheme that resolves the gate to epitaxy short issue and improves the reliability of the input/output device by adding a very thin Nitride layer that depends on the oxide (OX) undercut and removing the extrinsic gettering (EG) OX followed by TJ (i.e. photo layer for embedded silicon germanium (eSiGe) epitaxy) spacer deposition.

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Page 01 of 2

Title

New Spacer Scheme to Resolve the Gate to Epi Short Issue

Abstract

Disclosed is a new spacer scheme that resolves the gate to epitaxy short issue and improves the reliability of the input/output device by adding a very thin Nitride layer that depends on the oxide (OX) undercut and removing the extrinsic gettering (EG) OX followed by TJ (i.e. photo layer for embedded silicon germanium (eSiGe) epitaxy) spacer deposition.

Problem

A method is needed to address the issue of gate to epitaxy (epi) short and improve the reliability of the input/output (I/O) device.

With one current method (Figure 1), the thick extrinsic gettering (EG) oxide (OX) remains, especially for the fin sidewall. During the epi preclean, the OX is removed. Sometimes, the gate OX is also attacked, which causes gate to polycarbonate (PC) short or RX hole during the poly open process.

Figure 1: Current Method #1

A second method (Figure 2) removes the EG OX and re-ox (or skips re-OX) before TJ spacer dep, so the OX between TJ Nitride and silicon resolves the issue of method #1; however, during the EG OX removal, some OX undercut occurs under the poly. Either the TJ Nitride filling in or not the undercut, it impacts the I/O device performance variability and reliability.


Page 02 of 2

Figure 2: Current Method #2

Solution/Novel Contribution

The novel contribution is a scheme that includes adding a very thin Nitride layer (i.e. 2~5nm) that depends on the OX undercut and removing the tunnel gate (TG)...