Compound Semiconductor Superlattice Layer for Strain and Dopant Control
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Solution Overview
Problem
Existing semiconductor devices face challenges in enhancing charge carrier mobility and managing stress/strain due to material differences, leading to issues like excessive warping and inefficient dopant diffusion.
Innovation Solution
Incorporation of a superlattice layer with alternating semiconductor and non-semiconductor monolayers, such as silicon and oxygen or carbon, to form a mechanical interface that reduces stress, improves charge carrier mobility, and controls dopant diffusion, while also providing piezoelectric and ferroelectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If strained material layers are used to enhance charge carrier mobility, then device speed and efficiency are improved, but material warping and stress management become problematic
Solution Approach 1:
The patent divides the semiconductor structure into multiple alternating layers of different materials (e.g., SiGe/Si superlattice), creating segmented regions that can independently manage strain. This segmentation allows the structure to accommodate differential thermal expansion and mechanical stress without causing overall warping, while still providing the desired strain effect in the channel region for enhanced carrier mobility.
Solution Approach 2:
The patent applies local quality by creating specific strained regions within the semiconductor device. The superlattice structure is designed so that strain is localized to particular layers (e.g., SiGe layers) while other layers (e.g., Si layers) remain relatively strain-free. This allows the device to benefit from enhanced carrier mobility in strained regions while maintaining structural stability in unstrained regions, preventing overall warping.
2Speed
If alternating semiconductor and non-semiconductor monolayers are used to form superlattice, then charge carrier mobility is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent employs periodic action by creating a repeating pattern of alternating semiconductor and non-semiconductor monolayers in the superlattice structure. This periodic arrangement (e.g., SiGe/Si/SiGe/Si...) provides consistent strain effects and band structure modifications throughout the material, enhancing charge carrier mobility. The periodic structure can be manufactured using standard epitaxial growth techniques that deposit alternating layers in a cyclic process, managing the complexity through routine manufacturing steps.
3Reliability
If superlattice layer is used to manage stress and improve integration, then device performance is enhanced, but dopant diffusion control becomes more difficult
Solution Approach 1:
The patent uses the superlattice structure as an intermediary layer between the substrate and the active device regions. The alternating layers of different semiconductors (e.g., SiGe/Si) create a graded interface that gradually transitions material properties, managing stress and strain while controlling dopant diffusion. The superlattice acts as a buffer that prevents abrupt changes in crystal structure, thereby controlling how dopants diffuse through the structure during manufacturing.
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 superlattice layer enhances charge carrier mobility, reduces stress-related warping, and improves device integration by managing dopant diffusion, leading to improved performance and integration of Group III-N semiconductor devices.
Implementation Method 1
providing piezoelectric and ferroelectric properties
Implementation Method 2
providing piezoelectric and ferroelectric properties
Implementation Method 3
reduces stress, improves charge carrier mobility
Implementation Method 4
managing dopant diffusion
Data Source
AI summary
A semiconductor device may include a semiconductor substrate and a superlattice layer on the semiconductor substrate. The superlattice layer may include a plurality of stacked groups of layers, with each group of layers including a plurality of stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions. The semiconductor device may further include a Group III-N semiconductor stack including a plurality of layers of Group III-N semiconductor layers above the superlattice layer.