Quantum Dot Semiconductor Switching Device for Low Leakage Current
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Solution Overview
Problem
Conventional field effect transistors face challenges in scaling down to nanometer dimensions due to increased off-state leakage current and reduced on-current to off-current ratio, leading to high power consumption in semiconductor chips.
Innovation Solution
A semiconductor device employing a quantum dot structure with a semiconductor island encapsulated by dielectric material layers, where the thickness of these layers is less than 2 nm to enable quantum tunneling, allowing for low leakage current and effective switching even at low operational voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional field effect transistors are scaled down to nanometer dimensions, then device size is reduced, but off-state leakage current increases
Solution Approach 1:
The patent changes the fundamental operating mechanism from classical field effect to quantum tunneling by adjusting the energy barrier parameters. The source and drain regions are configured as quantum dots with discrete energy levels, and the tunnel barrier thickness is optimized to enable controlled quantum tunneling. This parameter change allows the device to achieve low leakage current through the quantum confinement effect while maintaining nanometer-scale dimensions.
Solution Approach 2:
The patent replaces the classical field effect mechanism with a quantum mechanical tunneling mechanism. Instead of relying on electric field modulation of carrier concentration as in conventional FETs, the device utilizes quantum tunneling through a potential barrier formed by the tunnel barrier layer. This substitution of the underlying physical mechanism enables the device to overcome the leakage current problem inherent in scaled conventional FETs.
2Use of energy by stationary object
If operational voltage is reduced for low power applications, then power consumption decreases, but the ratio between on-current and off-current decreases
Solution Approach 1:
The patent changes the current transport mechanism from drift-diffusion to quantum tunneling, which has a different voltage dependence. The tunneling current is exponentially dependent on the barrier height and width, allowing for steeper subthreshold slopes and higher on/off current ratios even at low voltages. The quantum dot energy levels are engineered to provide sharp turn-on characteristics that maintain high current ratios at reduced operational voltages.
Solution Approach 2:
The patent utilizes the dynamic response of quantum tunneling to gate voltage changes. The quantum dot system exhibits rapid switching between tunneling and blocked states in response to gate voltage modulation. This dynamic behavior enables efficient switching at low voltages because the quantum tunneling probability changes dramatically with small voltage variations, providing high gain and maintaining good on/off ratios.
3Productivity
If quantum tunneling is enabled by reducing dielectric material thickness, then switching efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the dielectric material from a conventional thick insulator to an ultra-thin tunnel barrier layer with specific thickness in the range of 1-3 nm. This parameter change enables quantum tunneling while the precise thickness control is achieved through atomic layer deposition or molecular beam epitaxy techniques. The specific material composition and thickness are optimized to provide the desired tunneling characteristics with acceptable manufacturing tolerances.
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 semiconductor device achieves low leakage current and efficient switching at low operational voltages, addressing the scaling challenges of conventional field effect transistors by utilizing quantum tunneling effects in the quantum dot structure.
Implementation Method 1
At least two portions of the at least one dielectric material layer have a thickness less than 2 nm to enable quantum tunneling effects
Data Source
AI summary
A semiconductor device includes a semiconductor island having at least one electrical dopant atom and encapsulated by dielectric materials including at least one dielectric material layer. At least two portions of the at least one dielectric material layer have a thickness less than 2 nm to enable quantum tunneling effects. A source-side conductive material portion and a drain-side conductive material portion abuts the two portions of the at least one dielectric material layer. A gate conductor is located on the at least one dielectric material layer between the source-side conductive material portion and the drain-side conductive material portion. The potential of the semiconductor island responds to the voltage at the gate conductor to enable or disable tunneling current through the two portions of the at least one dielectric material layer. Design structures for the semiconductor device are also provided.