Self-Aligned Coulomb Blockade Single-Electron Transistor
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Solution Overview
Problem
Conventional single-electron transistors require very low temperatures to operate and struggle with reliable manufacturing of the Coulomb blockade.
Innovation Solution
A semiconductor device with a thin channel region on a buried insulator, separated by notches from source and drain regions, and a gate structure, using CMOS fabrication processes to control dimensions and form a Coulomb blockade, enabling operation at high temperatures through quantum tunneling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional SET fabrication methods are used, then the device can be manufactured, but the Coulomb blockade dimensions cannot be controlled reliably and very low temperatures are required for operation
Solution Approach 1:
The patent employs self-aligned fabrication processes where the Coulomb blockade structure is automatically positioned relative to the quantum dot through sequential deposition and etching steps. The dielectric layer and metal electrodes are formed in a self-aligned manner, eliminating the need for separate alignment operations and ensuring precise dimensional control without additional complexity
Solution Approach 2:
The patent controls the Coulomb blockade dimensions by precisely adjusting fabrication parameters including dielectric layer thickness, metal electrode deposition thickness, and etch depths. These parameter changes enable reliable formation of the Coulomb blockade at room temperature by achieving the required dimensional precision through standard CMOS processes
2Ease of manufacture
If standard CMOS processes are used, then manufacturing is simplified, but the precision required for quantum tunneling effects cannot be achieved
Solution Approach 1:
The patent performs preliminary actions by first forming the semiconductor layer with embedded quantum dots, then sequentially depositing dielectric and metal layers that are later etched to create the Coulomb blockade structure. This preliminary structuring enables precise dimensional control while using standard CMOS-compatible processes
Solution Approach 2:
The patent introduces a dielectric layer as an intermediary between the quantum dot and metal electrodes. This dielectric mediator enables precise positioning and dimensional control of the Coulomb blockade structure while maintaining compatibility with standard CMOS fabrication processes
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
Enables single-electron transistors to operate effectively at room temperature by controlling the Coulomb blockade dimensions and potential barriers, allowing for efficient electron tunneling and current formation.
Implementation Method 1
A dielectric layer is deposited in the notches to create a Coulomb blockade between the channel region and the source and drain regions
Implementation Method 2
Single-electron transistors (SETs), which operate by quantum tunneling effects
Data Source
AI summary
Semiconductor devices include a thin channel region formed on a buried insulator. A source and drain region is formed on the buried insulator, separated from the channel region by notches. A gate structure is formed on the thin channel region.