Fin-like Transistor Dummy Gate for Strained Epitaxy
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Solution Overview
Problem
In the integrated circuit industry, epitaxy growth for strained semiconductor structures is hindered by facet defects formed during the formation of fin-like active regions, which constrain further growth and affect circuit performance.
Innovation Solution
A semiconductor structure and method that includes forming fin-like active regions with a dummy gate stack extending over the end portions, allowing epitaxy growth to occur without exposing dielectric isolation features, thus eliminating facet defects by offsetting recesses from isolation features and enabling strain-enhanced epitaxy features to be grown on semiconductor surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epitaxy growth is performed to form strained semiconductor structures, then carrier mobility is increased and circuit performance is enhanced, but facet defects are formed that constrain further epitaxy growth
Solution Approach 1:
A dummy gate stack is formed over the isolation feature and line end portions of the active region before epitaxy growth. This preliminary structure prevents facet defects from forming at the line ends during subsequent epitaxy processes, allowing strain-enhanced growth to proceed without interruption while maintaining circuit performance
2Ease of manufacture
If fin-like active regions are formed with standard gate structures, then device fabrication is simplified, but void defects occur at line end portions due to exposed dielectric isolation features
Solution Approach 1:
The dummy gate stack serves as an intermediary structure between the isolation feature and the active region line ends. It fills the space that would otherwise expose dielectric isolation features, preventing void defect formation during epitaxy growth while maintaining fabrication simplicity through integration with standard gate formation processes
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
The solution effectively eliminates facet defects and enhances carrier mobility, improving circuit performance by allowing strain-enhanced epitaxy growth without void defects, thereby improving the integrity and efficiency of fin-like field effect transistors.
Implementation Method 1
Epitaxy growth is a step implemented to form the strained structure
Implementation Method 2
strained semiconductor structures are used to increase the carrier mobility in the channel and enhance circuit performance
Data Source
AI summary
A method includes forming an isolation feature in a semiconductor substrate; forming a first fin-like active region and a second fin-like active region in the semiconductor substrate and interposed by the isolation feature; forming a dummy gate stack on the isolation feature, wherein the dummy gate extends to the first fin-like active region from one side and to the second fin-like active region from another side.