Gateless RF Switch with Capacitively-Coupled Contacts
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Solution Overview
Problem
Quality ohmic contact formation is a significant challenge in manufacturing wide band gap semiconductor devices, particularly during high temperature annealing, which leads to material degradation, and existing RF switches require complex contact annealing processes.
Innovation Solution
The development of a gateless RF switch with capacitively-coupled contacts that eliminates the need for contact annealing, using a self-aligned metallization process to form RF input, output, and control electrodes, thereby reducing material degradation and simplifying the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature annealing is used to form ohmic contacts, then contact quality is improved, but material degradation occurs
Solution Approach 1:
The patent removes the annealing step entirely from the contact formation process. By using a self-aligned metallization process where contacts are formed directly during the metallization sequence without subsequent thermal treatment, the harmful high-temperature annealing is extracted and eliminated, preventing material degradation while maintaining contact functionality.
Solution Approach 2:
The patent introduces a self-aligned metallization process as an intermediary method between conventional ohmic contact formation and the final device structure. This intermediary process uses precisely controlled metal deposition and patterning to create contacts with appropriate electrical characteristics without requiring thermal annealing, thus mediating between contact quality requirements and material preservation.
2Reliability
If contact annealing process is used, then contact resistance is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent merges the contact formation step with the self-aligned metallization process. By combining what were previously separate operations (contact formation and metallization) into a single integrated process sequence, the manufacturing complexity is reduced. The contacts are formed as an inherent part of the metallization steps rather than as a separate annealing process.
Solution Approach 2:
The patent extracts and removes the annealing process from the manufacturing sequence. By taking out the thermal treatment step entirely and replacing it with a self-aligned metallization approach, the overall process complexity is reduced while still achieving the necessary contact resistance characteristics through precise metal layer deposition and patterning.
3Ease of operation
If conventional RF switch design is used, then switching function is achieved, but insertion loss increases
Solution Approach 1:
The patent applies local quality optimization by creating capacitively-coupled contacts with specific electrical characteristics at the contact regions. The self-aligned metallization process enables precise control of contact geometry and positioning, creating localized capacitive coupling that minimizes resistive losses in the RF signal path while maintaining the switching function through the underlying device structure.
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 solution results in RF switches with low contact resistance at high frequencies, achieving low insertion loss and high power switching capabilities without the need for annealing, enabling efficient operation in the gigahertz range.
Implementation Method 1
at least one of the input and output contacts is capacitively coupled to the conducting channel
Data Source
AI summary
A switch includes an input contact and an output contact to a conducting channel. At least one of the input and output contacts is capacitively coupled to the conducting channel. A control contact is located outside of a region between the input and output contacts, and can be used to adjust the switch between on and off operating states. The switch can be implemented as a radio frequency switch in a circuit.