Hyper-abrupt Varactor Superlattice Junction Reducing Carrier Scattering
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Solution Overview
Problem
Current semiconductor devices face limitations in enhancing charge carrier mobility and performance due to issues like alloy scattering and diffusion in thin layers, which affect device efficiency and reliability.
Innovation Solution
The introduction of a hyper-abrupt junction region with a superlattice structure, comprising stacked semiconductor and non-semiconductor monolayers, which reduces effective mass and enhances mobility by blocking inter-diffusion and scattering, and providing a common energy band structure for improved conductivity and device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional semiconductor structures are used, then manufacturing is simpler, but charge carrier mobility is limited due to alloy scattering and diffusion
Solution Approach 1:
The semiconductor structure is segmented into multiple thin monolayer sheets (e.g., SiC monolayers) separated by insulating layers. This segmentation creates a superlattice structure where each layer is thinner than the mean free path of charge carriers, effectively reducing alloy scattering and enhancing mobility while maintaining manufacturability through controlled layering
Solution Approach 2:
Insulating layers are introduced as intermediary elements between semiconductor monolayers. These intermediary layers prevent inter-diffusion of dopants and atoms between adjacent semiconductor layers, blocking scattering mechanisms while allowing the overall structure to maintain electrical conductivity through the semiconductor paths
2Speed
If thin semiconductor layers are used to reduce scattering, then mobility improves, but inter-diffusion increases
Solution Approach 1:
Insulating layers serve as intermediary barriers between thin semiconductor monolayers. These intermediaries physically prevent inter-diffusion of atoms and dopants between adjacent semiconductor layers, maintaining compositional stability while allowing the thin-layer structure to reduce scattering and enhance mobility
Solution Approach 2:
The structure combines semiconductor monolayers with insulating layers to form a composite superlattice material. This composite approach leverages the high mobility potential of thin semiconductor layers while using the insulating components to prevent detrimental inter-diffusion, achieving both improved speed and compositional stability
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 achieves higher charge carrier mobility, reduces ionized impurity scattering, and enhances device performance by lowering conductivity effective mass, making it suitable for advanced semiconductor devices with improved mobility and reduced diffusion.
Implementation Method 1
providing a common energy band structure for improved conductivity and device performance
Implementation Method 2
blocking inter-diffusion and scattering
Data Source
AI summary
A semiconductor device may include a substrate and a hyper-abrupt junction region carried by the substrate. The hyper-abrupt junction region may include a first semiconductor layer having a first conductivity type, a first superlattice layer on the first semiconductor layer, a second semiconductor layer on the first superlattice layer and having a second conductivity type different than the first conductivity type, and a second superlattice layer on the second semiconductor layer. The semiconductor device may further include a first contact coupled to the hyper-abrupt junction regions and a second contact coupled to the substrate to define a varactor. The first and second superlattices may each include stacked groups of layers, with each group of layers including 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.