Quantum Well Getter Structure for Radiation-Hardened FETs
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Solution Overview
Problem
Microelectronic devices, particularly field-effect transistors (FETs), are vulnerable to ionizing radiation, which can cause charge buildup, malfunctions, and failures due to the creation of electron-hole pairs leading to excess charges and potential device burnout.
Innovation Solution
Incorporation of a quantum structure getter (QSG) in microelectronic devices, comprising a material stack with a capping layer, high band gap barrier layers, small band gap quantum structures, and a substrate, positioned in close proximity to the conductive channel to form a quantum well charge getter. This structure traps and confines electron-hole pair wave functions, reducing ionized photocurrent and hardening the device against ionizing radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heavy shielding is used to protect microelectronic devices from ionizing radiation, then device reliability is improved, but device weight and volume increase significantly
Solution Approach 1:
The patent extracts the radiation protection function from the main device structure by incorporating a separate quantum structure getter layer. This getter layer specifically captures excess charges generated by ionizing radiation, removing the harmful effect without requiring heavy shielding materials. The quantum structures are positioned beneath the active region to selectively trap charges while maintaining device performance.
Solution Approach 2:
The patent changes the band gap parameter of the semiconductor structures by incorporating quantum wells with different band gap energies. The quantum structures have smaller band gaps than the barrier layers, creating energy states that preferentially trap excess charges. This parameter change enables selective charge capture without affecting the main device operation.
2Reliability
If heavy shielding is used to protect microelectronic devices from ionizing radiation, then device reliability is improved, but device volume increases significantly
Solution Approach 1:
The patent nests the quantum structure getter layer within the existing device architecture, placing it between the substrate and the active region. This nested structure provides radiation protection as an integrated component rather than as an external shielding layer, eliminating the need for additional volume while maintaining reliability.
3Reliability
If quantum structure getter is incorporated to reduce excess charges, then device reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the semiconductor structure into distinct functional layers with different band gap properties. The quantum wells are separated from the active region by barrier layers, creating discrete zones for charge generation, transport, and trapping. This segmentation allows independent optimization of each layer's function while maintaining overall device simplicity.
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 quantum structure getter significantly reduces excess charges caused by ionizing radiation, achieving a greater than 99% reduction in ionized photocurrent, thereby enhancing device performance and ensuring sustained operation in harsh radiation environments without the need for heavy shielding.
Implementation Method 1
The quantum structures are positioned in close proximity to the conductive channel to form a quantum well charge getter. The getter forms a low energy area beneath the FET, which traps and confines electron-hole pair wave functions produced from ionizing radiation
Implementation Method 2
causing the wave functions overlap, recombine, and produce light emission. The quantum structures getter the wave functions, which reduces the ionized photocurrent that reaches the conducting channel
Implementation Method 3
The quantum structures getter the wave functions, which reduces the ionized photocurrent that reaches the conducting channel, thereby hardening the microelectronic device against ionizing radiation
Data Source
AI summary
A microelectronic device that is radiation hardened through the incorporation of a quantum structure getter (QSG) is provided. The device, such as a field effect transistor (FET) includes a conductive channel and a material stack comprising: a capping layer, one or more barrier layers comprising a high band gap, one or more quantum structures comprising a small band gap, and a substrate. The quantum structures are positioned in close proximity to the conductive channel to form a quantum well charge getter. The getter forms a low energy area beneath the FET, which traps and confines electron-hole pair wave functions produced from ionizing radiation, causing the wave functions overlap, recombine, and produce light emission. The quantum structures getter the wave functions, which reduces the ionized photocurrent that reaches the conducting channel, thereby hardening the microelectronic device against ionizing radiation.