Gateless RF Switch with Capacitive Contacts for Low Loss
Find Innovative SolutionsGenerate Solutions
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 face issues with high insertion loss and material reliability for gigahertz frequency applications.
Innovation Solution
The development of a gateless RF switch with capacitively-coupled contacts that eliminates the need for contact annealing, using self-aligned metallization and Schottky or metal-oxide-semiconductor structures to reduce material degradation and achieve low contact resistance, especially at frequencies above 2 gigahertz, while allowing for low-loss high-power RF switching.
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 capacitively-coupled contacts where the control electrode is separated from the channel by a dielectric layer, the invention extracts the harmful high-temperature annealing process while maintaining effective contact control through capacitive coupling at lower temperatures.
Solution Approach 2:
The patent introduces a dielectric layer as an intermediary between the control electrode and the semiconductor channel. This dielectric mediator enables capacitive coupling that controls the channel without requiring direct ohmic contact formation through high-temperature annealing, thus avoiding material degradation while maintaining control functionality.
2Reliability
If conventional RF switch design is used, then basic switching function is achieved, but insertion loss exceeds acceptable levels
Solution Approach 1:
The patent changes the fundamental operating parameters of the switch by using capacitive coupling instead of direct ohmic contacts. This parameter change enables control through electric field effects rather than resistive control, reducing insertion loss to below one decibel while maintaining switching functionality through gate voltage control.
3Power
If high power switching capability is achieved, then RF performance is improved, but material reliability deteriorates
Solution Approach 1:
The patent replaces the mechanical/thermal process of high-temperature annealing with an electrical field-based capacitive coupling mechanism. This substitution allows high power switching capability to be achieved through electric field control rather than thermal processing, maintaining material reliability while enabling high RF power operation.
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 solution provides a low-loss, high-isolation RF switch with reduced material degradation and increased operating voltage, capable of achieving insertion loss below one decibel and isolation of thirty decibels across a wide frequency range, from one to eleven gigahertz.
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.