SAW Superlattice Structure for Carrier Mobility and Diffusion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices lack enhancements in charge carrier mobility and material diffusion, leading to inferior performance and scattering effects.
Innovation Solution
A semiconductor superlattice structure with alternating semiconductor and non-semiconductor monolayers, such as silicon and oxygen, is introduced to reduce impurity scattering and enhance mobility, while also providing piezoelectric and ferroelectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor structures are used, then device simplicity is maintained, but charge carrier mobility is insufficient and scattering effects increase
Solution Approach 1:
The semiconductor structure is segmented into multiple alternating layers of different materials (e.g., Si/SiGe, GaAs/AlGaAs) forming a superlattice. Each layer has a thickness on the order of monolayers to a few micrometers, creating a periodic structure that enables band engineering to enhance carrier mobility while maintaining manageable device complexity through systematic repetition of the pattern
Solution Approach 2:
The patent employs composite material systems where different semiconductor materials with distinct band structures are combined in alternating layers. This composite approach allows exploitation of favorable properties from each material (e.g., high mobility in one material, lattice matching in another) to achieve overall enhanced performance that neither material could provide alone
2Reliability
If impurity scattering is reduced to improve mobility, then charge carrier mobility increases, but device performance becomes inferior without proper doping control
Solution Approach 1:
The superlattice structure implements local quality variations by creating regions with different doping concentrations and material compositions at specific locations within the device. This allows optimization of carrier mobility in transport regions while maintaining adequate doping for carrier generation and collection in active regions, resolving the contradiction between reducing scattering and maintaining device performance
Solution Approach 2:
The patent systematically varies critical parameters including layer thickness, material composition ratios, and doping concentrations across different regions of the superlattice. By optimizing these parameters, the structure achieves reduced impurity scattering in key regions while maintaining overall device performance through coordinated parameter adjustment throughout the device architecture
3Reliability
If dopant diffusion is not blocked, then manufacturing is simpler, but material diffusion causes scattering and reduces mobility
Solution Approach 1:
The superlattice introduces intermediate layers with specific material compositions and structures that act as diffusion barriers between doped regions. These intermediate layers prevent unwanted dopant diffusion while maintaining electrical connectivity and carrier transport, thereby reducing scattering without requiring overly complex manufacturing processes
Solution Approach 2:
The patent incorporates diffusion barrier layers and carefully designed interface structures during the initial fabrication sequence. By establishing these protective structures before dopant introduction and activation, the design prevents material diffusion issues from developing, simplifying subsequent manufacturing steps while ensuring high carrier mobility through reduced scattering
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 structure improves charge carrier mobility, reduces scattering, and enhances device performance by confining carriers and acting as a barrier to dopant diffusion, suitable for applications like surface acoustic wave devices.
Implementation Method 1
electrons having a smaller effective mass, and which have been induced by an electric field applied to the gate electrode, are confined in the second silicon layer
Implementation Method 2
a poled region having a net electrical dipole moment and comprising a semiconductor layer and at least one non-semiconductor monolayer constrained within a crystal lattice of the semiconductor layer
Implementation Method 3
Surface acoustic wave (SAW) devices including a superlattice and related methods
Data Source
AI summary
An electronic device may include a poled region having a net electrical dipole moment and including a semiconductor layer and at least one non-semiconductor monolayer constrained within a crystal lattice of the silicon layer. The electronic device may further include a plurality of spaced apart alternating N-type and P-type regions within the poled region to align the net electrical dipole moment of the poled region, and at least one electrode associated with the poled region. The poled region may be a superlattice, for example.