Transistor End Cap Metal Structure for Radiation Hardening
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Solution Overview
Problem
Integrated circuits in space environments suffer from ionizing radiation-induced leakage currents due to charge accumulation, which existing radiation-hardened designs address at the expense of increased area usage.
Innovation Solution
A transistor architecture featuring an 'end cap' metal structure connected to ground potential to steer and repel charge away from critical areas, preventing further buildup and leakage, while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional annular transistor designs are used to suppress radiation-induced leakage currents, then reliability is improved, but area usage increases
Solution Approach 1:
The annular gate is segmented into discrete sections (first gate section, second gate section, third gate section) rather than forming a complete continuous ring. This segmentation maintains the radiation-hardening benefits of the annular structure while reducing the total area occupied by the gate structure, directly resolving the contradiction between reliability and area usage.
Solution Approach 2:
The invention extracts and removes portions of the annular gate structure, specifically creating gaps between gate sections. By taking out unnecessary parts of the continuous ring, the design maintains essential radiation suppression functionality while reducing area consumption, thus balancing reliability improvement with area efficiency.
2Reliability
If redundancy and spacing of electronic circuits are implemented, then radiation resistance is improved, but device complexity increases
Solution Approach 1:
Instead of applying redundancy and spacing globally across the entire circuit, the invention applies radiation-hardening locally at the transistor level through the segmented annular gate structure. This localized approach provides radiation resistance without requiring complex redundant circuit designs or increased spacing between circuits, thereby reducing overall device complexity.
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
Effectively suppresses ionizing dose-induced leakage currents without the area penalty of traditional annular designs, ensuring reliable operation while minimizing power drain and overheating.
Implementation Method 1
The suppression architecture of the present invention uses the field established by coupling the metal structure to ground
Implementation Method 2
Electrons trapped in high earth orbits and electrons and protons trapped in low and medium earth orbits cause a high level of ionizing radiation in space. Such ionizing radiation causes an accumulation of charge in electronic circuits
Implementation Method 3
Electron-hole pairs generated in the bulk silicon of an integrated circuit do not present a severe problem, as the electrons and holes recombine rapidly
Data Source
AI summary
A total ionizing dose suppression architecture for a transistor and a transistor circuit uses an “end cap” metal structure that is connected to the lowest potential voltage to overcome the tendency of negative charge buildup during exposure to ionizing radiation. The suppression architecture uses the field established by coupling the metal structure to the lowest potential voltage to steer the charge away from the critical field (inter-device) and keeps non-local charge from migrating to the “birds-beak” region of the transistor, preventing further charge buildup. The “end cap” structure seals off the “birds-beak” region and isolates the critical area. The critical area charge is source starved of an outside charge. Outside charge migrating close to the induced field is repelled away from the critical region. The architecture is further extended to suppress leakage current between adjacent wells biased to differential potentials.