Uniform Thin Silicide on Epitaxial Source/Drain Contacts
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Solution Overview
Problem
In semiconductor manufacturing, particularly for Fin FET devices, the formation of silicide layers on epitaxial source/drain structures results in an uneven interface and varying thickness, which affects device performance and reliability.
Innovation Solution
A method involving the deposition of an amorphous first material layer followed by a metal layer, and subsequent annealing to form a silicide layer, ensuring a uniform thickness and smooth interface with the underlying semiconductor layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a silicide layer is formed directly on an epitaxial source/drain structure, then the manufacturing process is simple, but the interface becomes uneven and the layer thickness varies
Solution Approach 1:
An amorphous silicon layer is deposited on the epitaxial source/drain structure before forming the silicide layer. This preliminary amorphous layer serves as a buffer that enables subsequent uniform silicide formation, resolving the contradiction by preparing the surface in advance to achieve both manufacturability and precision.
Solution Approach 2:
The amorphous silicon layer acts as an intermediary between the epitaxial source/drain structure and the silicide layer. This intermediate layer mediates the interface formation process, ensuring uniform thickness and smooth interface while maintaining a straightforward manufacturing process.
2Reliability
If the silicide layer thickness is reduced to improve device performance, then contact resistance decreases, but controlling the thickness uniformly becomes more difficult
Solution Approach 1:
The amorphous silicon layer is deposited to a controlled thickness before silicide formation. This preliminary layer thickness control enables the final silicide layer to achieve uniform thin dimensions with precise control, lowering contact resistance while maintaining manufacturing precision.
Solution Approach 2:
By changing the physical state of the silicon layer from crystalline (epitaxial) to amorphous, the deposition and reaction characteristics are improved. This parameter change enables better thickness control and uniformity in the final silicide layer, achieving both low contact resistance and precise thickness control.
3Ease of manufacture
If a thicker silicide layer is formed to ensure complete coverage, then manufacturing is easier, but the interface quality deteriorates
Solution Approach 1:
The amorphous silicon layer serves as an intermediary that enables complete silicide coverage while maintaining a smooth interface. This intermediate layer ensures uniform reaction across the surface, achieving both complete coverage and high interface quality.
Solution Approach 2:
Transforming the silicon layer to amorphous state changes its deposition and reaction properties, allowing for better interface quality. The amorphous structure enables uniform silicide formation that provides complete coverage while maintaining a smooth interface, resolving the contradiction between ease of manufacture and interface quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the fabrication of a thin, uniform silicide layer with precise thickness control, improving the interface quality and reducing contact resistance, thereby enhancing the performance and reliability of the semiconductor device.
Implementation Method 1
subsequent annealing to form a silicide layer
Implementation Method 2
form an alloy layer of the amorphous first material and the metal second material
Implementation Method 3
form a silicide layer
Implementation Method 4
a first layer containing an amorphous first material is formed by a deposition process
Implementation Method 5
formed by a deposition process
Data Source
AI summary
In a method of manufacturing a semiconductor device, a first layer containing an amorphous first material is formed by a deposition process over a semiconductor layer. A second layer containing a metal second material is formed over the first layer. A thermal process is performed to form an alloy layer of the amorphous first material and the metal second material.