FinFET Gate Replacement for In-Plane Tensile Strain Control
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Solution Overview
Problem
The semiconductor industry faces challenges in manufacturing high-performance FinFET devices due to limitations in achieving controlled strain and carrier mobility, particularly in inducing in-plane tensile strain in channel regions for enhanced device performance.
Innovation Solution
The method involves forming a stress material layer in the source/drain recesses of a FinFET device, which induces tensile strain on the channel region, and subsequent replacement of the dummy gate with a metal gate stack that maintains this strain, combined with epitaxy structures to enhance carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dummy gate structure is formed first and then stress material is deposited, then in-plane tensile strain can be induced in the channel region, but the dummy gate must be removed and replaced adding process complexity
Solution Approach 1:
A dummy gate structure is formed preliminarily before stress material deposition to enable subsequent strain induction. The dummy gate serves as a placeholder that allows stress material to be deposited conformally on its sidewalls, which then induces in-plane tensile strain in the channel region when the dummy gate is removed and replaced with a metal gate stack.
Solution Approach 2:
The dummy gate structure acts as an intermediary element that facilitates stress material deposition. It provides the necessary geometric structure for conformal deposition of stress material on sidewalls, and serves as a temporary structure that is later replaced by the functional metal gate while leaving the stress-induced strain in place.
2Reliability
If metal gate stack is formed after stress material deposition, then the strain is maintained in the channel region, but additional processing steps are required
Solution Approach 1:
The stress material is deposited preliminarily on the dummy gate sidewalls before the metal gate is formed. This preliminary action ensures that the strain-inducing stress material is already in place and will be maintained when the metal gate stack is subsequently formed, enabling reliable device performance without requiring additional strain induction steps later.
Solution Approach 2:
The strain induction action continues through the gate replacement process. The stress material deposited on the dummy gate sidewalls maintains its strain-inducing configuration as the dummy gate is removed and the metal gate is formed, ensuring continuous useful action of strain maintenance throughout the manufacturing process.
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 configuration improves the performance of semiconductor devices by maintaining in-plane tensile strain and increasing carrier mobility, leading to better device performance and reliability.
Implementation Method 1
forming a stress material layer in the source/drain recesses of a FinFET device, which induces tensile strain on the channel region
Data Source
AI summary
A method for manufacturing a semiconductor device includes forming a semiconductor fin on a substrate. A dummy gate structure is formed crossing the semiconductor fin. The dummy gate structure is replaced with a metal gate structure. An epitaxial structure is formed in the semiconductor fin after replacing the dummy gate structure with the metal gate structure.