Fin End Extension Structure to Prevent Epitaxy Faucet Defects
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Solution Overview
Problem
The epitaxy growth process in semiconductor structures is sensitive to the structure of active regions and can result in faucet defects, constraining further growth and affecting the integrity of strained semiconductor structures.
Innovation Solution
A semiconductor structure and method that includes forming fin-like active regions with a dummy gate stack disposed on isolation features, offsetting recesses from the isolation region to prevent faucet defects and enable epitaxy growth for enhanced strain effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epitaxy growth is performed on fin-type active regions, then strained semiconductor structures are formed to increase carrier mobility, but faucet defects are formed that constrain further epitaxy growth
Solution Approach 1:
A dummy gate stack is formed over the isolation feature before epitaxy growth. This preliminary structure prevents faucet defects from forming at the interface between the active region and isolation feature, thereby eliminating the constraint on epitaxy growth while maintaining structural integrity
2Area of stationary object
If recesses are positioned close to isolation regions, then device density is increased, but void formation occurs between epitaxy features and isolation structures
Solution Approach 1:
The dummy gate stack serves as an intermediary structure between the epitaxy feature and the isolation feature. It fills the space that would otherwise form voids, allowing high device density while preventing void formation and maintaining epitaxy feature integrity
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
Eliminates faucet defects and allows for epitaxy growth on semiconductor surfaces, enhancing carrier mobility and circuit performance by preventing void formation between epitaxy features and isolation structures.
Implementation Method 1
Epitaxy growth is a step implemented to form the strained structure
Data Source
AI summary
A semiconductor structure includes an isolation feature formed in the semiconductor substrate and a first fin-type active region. The first fin-type active region extends in a first direction. A dummy gate stack is disposed on an end region of the first fin-type active region. The dummy, gate stack may overlie an isolation structure. In an embodiment, any recess such as formed for a source/drain region in the first fin-type active region will be displaced from the isolation region by the distance the dummy gate stack overlaps the first fin-type active region.