Strained Semiconductor Substrate via Porous Layer Bending
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for forming biaxially strained semiconductor substrates are complex and result in high fault densities, requiring different materials for N-channel and P-channel MOS transistors and being size-dependent, while biaxial strain application is not uniformly achievable.
Innovation Solution
A method involving the formation of a porous semiconductor material layer on the opposite surface of a semiconductor substrate, followed by annealing processes to achieve uniform tensile or compressive biaxial strain, which improves carrier mobility by modifying the substrate's curvature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous semiconductor material layer is formed on the second surface to bend the substrate, then uniform biaxial strain is achieved with improved carrier mobility, but the substrate curvature changes which may affect subsequent processing
Solution Approach 1:
A layer of porous semiconductor material is formed on the second surface of the substrate. The porous structure creates differential stress that bends the substrate to apply uniform biaxial strain to the transistor channels, improving carrier mobility by approximately 80% for electrons and 60% for holes.
Solution Approach 2:
The substrate is intentionally bent into a curved shape by forming the porous material layer on the second surface. This curvature induces the desired biaxial strain in the channel regions while the patent acknowledges this shape change as a trade-off for achieving superior electrical performance.
2Reliability
If known methods are used to form biaxially strained substrates, then carrier mobility is improved, but the density of faults (dislocations) becomes very high
Solution Approach 1:
The porous semiconductor material layer provides a controlled method to induce strain without creating high dislocation densities. The porous structure allows for strain application through controlled bending rather than through high-strain epitaxial growth that would generate defects.
Solution Approach 2:
The method changes the physical state of a portion of the substrate by creating a porous structure, which has different mechanical properties than dense semiconductor material. This parameter change enables strain application through bending while avoiding the defect generation associated with traditional strained layer epitaxy.
3Reliability
If known methods are used to form uniaxially strained substrates, then carrier mobility is improved, but the implementation becomes relatively complex requiring different materials for N-channel and P-channel MOS transistors
Solution Approach 1:
The porous material layer formation method provides a universal approach to strain application that works for both N-channel and P-channel MOS transistors. Unlike uniaxial strain methods that require different material systems (SiGe for PMOS, SiC for NMOS), this method applies biaxial strain uniformly to all transistor types through substrate bending, simplifying the manufacturing process.
Solution Approach 2:
The method creates homogeneous biaxial strain across the entire substrate surface, affecting all transistor channels uniformly regardless of type. This homogeneous strain application eliminates the need for different material compositions for different transistor types, reducing device complexity.
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 method enables easy implementation of uniform biaxial strain, enhancing electron and hole mobility by approximately 80% and 60% respectively, while reducing fault densities and maintaining substrate planarity.
Implementation Method 1
forming at least portions of a layer of a porous semiconductor material on the side of a second surface of the semiconductor substrate, opposite to the first surface, to bend the semiconductor substrate
Implementation Method 2
followed by annealing processes to achieve uniform tensile or compressive biaxial strain
Data Source
AI summary
A method for forming an electronic circuit on a strained semiconductor substrate, including the steps of: forming, on a first surface of a semiconductor substrate, electronic components defining electronic chips to be sawn; and forming at least portions of a layer of a porous semiconductor material on the side of a second surface of the semiconductor substrate, opposite to the first surface, to bend the semiconductor substrate.