MOS Capacitor Quantum Well for Room Temperature Operation
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Solution Overview
Problem
Integrating quantum well devices in silicon integrated circuits with energy level separations greater than 50 meV for room temperature operation has been challenging.
Innovation Solution
A gated quantum well device is formed in a metal oxide semiconductor (MOS) capacitor structure with an inversion region under the MOS gate, creating a quantum well less than 20 nanometers wide, allowing for precise separation of electron or hole energy levels, and can be operated as a precision charge pump without increasing process cost or complexity in CMOS integrated circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If quantum well devices are integrated in silicon integrated circuits with energy level separations greater than 50 meV for room temperature operation, then precise charge handling capabilities are achieved, but device fabrication complexity increases
Solution Approach 1:
The patent combines the quantum well device fabrication with standard CMOS工艺流程, integrating the quantum well structure formation into existing capacitor and transistor fabrication steps. This merging approach allows quantum well devices to be manufactured using conventional CMOS processes without adding significant fabrication complexity, while achieving the required energy level separations greater than 50 meV for room temperature operation
Solution Approach 2:
The patent achieves precise energy level separations by controlling critical parameters including quantum well width (less than 20 nanometers), doping concentrations, and gate oxide thickness. By precisely adjusting these parameters during fabrication, the device achieves energy level separations greater than 50 meV suitable for room temperature operation, while maintaining compatibility with standard CMOS fabrication processes
2Measurement precision
If quantum well width is reduced to less than 20 nanometers to achieve desirable separation of electron or hole energy levels, then energy level separation precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs preliminary actions in the fabrication process, including pre-defining the quantum well region through capacitor structure formation before actual quantum well creation, and using pre-established doping profiles to control the quantum well width. These preliminary steps ensure that the quantum well width is precisely controlled at less than 20 nanometers, achieving the required energy level separations without demanding excessive manufacturing precision
Solution Approach 2:
The patent uses the gate oxide layer and gate electrode as intermediaries to control and define the quantum well dimensions. The gate structure serves as a template that precisely defines the quantum well width during fabrication, enabling accurate control of the quantum well at less than 20 nanometers width while simplifying the direct manufacturing precision requirements
3Ease of manufacture
If standard CMOS fabrication processes are used for quantum well devices, then ease of manufacture is improved, but device performance may be compromised
Solution Approach 1:
The patent designs the quantum well device structure to be universal with standard CMOS components, particularly using the same capacitor and transistor fabrication processes. The quantum well device can be fabricated using standard CMOS工艺流程 including oxide growth, doping, and patterning, making it easy to manufacture while maintaining device performance through proper structure design
Solution Approach 2:
The patent applies local quality by modifying specific regions of the CMOS structure to create the quantum well while maintaining standard CMOS characteristics in other areas. The quantum well region has specialized doping and dimensional characteristics, while the rest of the device uses standard CMOS processes, ensuring both ease of manufacture and device performance
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 the fabrication of gated quantum well devices in CMOS ICs that can operate effectively at room temperature with precise charge handling capabilities, facilitating advanced precision circuits.
Implementation Method 1
An inversion region under the MOS gate forms a quantum well that is preferably less than 20 nanometers wide, causing desirable separation of electron or hole energy levels in the quantum well
Implementation Method 2
The gated quantum well device may be operated as a precision charge pump
Data Source
AI summary
A gated quantum well device formed as an MOS capacitor is disclosed. The quantum well is an inversion region less than 20 nanometers wide under the MOS gate. The device may be fabricated in either polarity, and integrated into a CMOS IC, configured as a quantum dot device or a quantum wire device. The device may be operated as a precision charge pump, with a minority carrier injection region added to speed well filling.