3D Polycrystalline Semiconductor Quantum Dot Carrier
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Solution Overview
Problem
Existing semiconductor technologies face limitations in achieving high switching speeds and preventing avalanche breakdown in low band gap semiconductors due to the narrow thickness of quantum well structures, which restricts current density and power management capabilities.
Innovation Solution
The development of a three-dimensional polycrystalline semiconductor material with nanoscale grains that induce quantum-size effects, allowing for the formation of a three-dimensional electron gas within a bulk material layer, enabling higher carrier mobility and reduced risk of avalanche breakdown through the integration of metallic or insulating materials at grain boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If quantum well structures are used to achieve high switching speeds, then carrier mobility is improved, but the narrow thickness restricts current density and power management capabilities
Solution Approach 1:
The patent transitions from two-dimensional quantum well structures to three-dimensional quantum dot structures distributed throughout a bulk semiconductor layer. This dimensional change allows the conduction channel thickness to be increased from nanometer-scale thin films to micrometer-scale bulk layers, enabling higher current density while maintaining high carrier mobility through the quantum size effects of the distributed quantum dots.
Solution Approach 2:
The patent changes the physical parameters of the semiconductor structure by increasing the conduction channel thickness from 20-50 nm in quantum wells to greater than 50 nm (up to micrometer scale) in quantum dot structures. This parameter change allows simultaneous achievement of high carrier mobility (through quantum size effects) and high current density capability (through increased bulk volume), resolving the contradiction between switching speed and power management capability.
2Speed
If thin quantum well structures are used to achieve high electron mobility, then switching speed is improved, but the risk of avalanche breakdown increases
Solution Approach 1:
The patent uses three-dimensional quantum dot structures distributed throughout a bulk semiconductor layer instead of two-dimensional quantum wells. This allows the conduction channel to extend through the bulk material with thickness greater than 50 nm, providing sufficient distance for carrier scattering and energy dissipation, thereby reducing impact ionization and avalanche breakdown risk while maintaining high carrier mobility through quantum size effects.
Solution Approach 2:
The patent introduces a bulk semiconductor material as an intermediary medium that contains distributed quantum dots. This bulk material provides a three-dimensional conduction pathway that mediates between the high carrier mobility requirement (achieved through quantum dot size effects) and the avalanche breakdown resistance requirement (achieved through increased conduction channel thickness and bulk material properties).
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
This approach enables high-speed semiconductor devices with thicker conduction channels, supporting higher currents at lower current densities and reducing the risk of impact ionization, thus enhancing power management and switching speed capabilities.
Implementation Method 1
the nanoscale texture of the semiconducting material induces quantum-size effects within the polycrystalline grains that endow the bulk semiconductor with electrical or optical properties (herein referred to as 'general dielectric properties') of a three-dimensional (3D) electron gas
Implementation Method 2
The semiconductor layers 5,7 provide higher ionization thresholds that prevent currents flowing in the primary conduction channel in the central layer 6 from undergoing avalanche breakdown through impact ionization processes
Data Source
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AI summary
A three-dimensional polycrystalline semiconductor material provides a major ingredient forming individual crystalline grains having a nominal maximum grain diameter less than or equal to 50 nm, and a minor ingredient forming boundaries between the individual crystalline grains.