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A Method to Grow Uniform embedded SiGe on silicon wafers of diameter 300mm, 450mm and beyond

IP.com Disclosure Number: IPCOM000244938D
Publication Date: 2016-Feb-03
Document File: 6 page(s) / 100K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to improve the uniformity of embedded silicon germanium (eSiGe) cavity etch and deposition.

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Title

A Method to Grow Uniform embedded SiGe on silicon wafers of diameter 300mm, 450mm and beyond

Abstract

Disclosed is a method to improve the uniformity of embedded silicon germanium (eSiGe) cavity etch and deposition.

Problem

Conventional embedded Silicon is grown on Silicon wafers that are non-uniform toward the edge of the wafer. Non-uniformity of embedded silicon germanium (SiGe) across the wafers arises due to either cavity etch non uniformity or SiGe deposition non- uniformity. Further, the eSiGe has several layers of SiGe with varying Ge composition or silicon.

Non-uniformity creates threshold Voltage (Vt) and on-current non-uniformity across the wafer, which in turn results in higher variation and product yield loss.

Traditionally, uniformity of embedded silicon germanium (eSiGe) is achieved by tweaking chemistry of the growth precursor and tuning the temperature across the wafer.

Solution/Novel Contribution

The novel contribution is a method to improve the uniformity of eSiGe cavity etch and deposition. This method significantly improves eSiGe uniformity across the wafer and the product yield.

Method/Process

Figure 1(a) and (b): A typical cavity and deposited SiGe in a Positive Field Effect Transistor (PFET) with sigma shaped cavity.

(a)


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(b)

Figure 2(a) and (b): The PFET with a U-shaped cavity.
(a)


(b)


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Figure 3: Device can be Shallow Trench Isolation (STI) bounded

Figure 4: Device can be STI poly bounded

The novel method enables manufacturing as a Gate first or Gate last or as conventional Poly Silicon Oxynitride (SiON) technology.

Figure 5 (a) and (b): Showing how the cavity depth and total thickness vary across the wafer

(a)


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(b)

Further, the total thickn...