RF Switch FET Stack With Non-Uniform Gate Lengths for Voltage Handling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radio-frequency (RF) switching devices face challenges in achieving high voltage handling capacity while maintaining low ON-resistance (Ron) and improved linearity performance, especially in high-power applications where parasitic effects limit the maximum achievable voltage handling capability.
Innovation Solution
The implementation of a switching device with a stack of field-effect transistors (FETs) having a non-uniform distribution of a parameter, such as gate length, which results in a higher voltage handling capacity, reduced ON-resistance, and improved linearity performance compared to a similar stack with a uniform distribution of the parameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a higher stack height is utilized to allow an RF switch to withstand higher power, then voltage handling capacity is improved, but ON-resistance increases
Solution Approach 1:
The patent applies local quality by implementing a non-uniform distribution of gate lengths among FETs in the stack, where FETs experiencing higher voltage stress have longer gate lengths for enhanced breakdown voltage, while FETs with lower voltage stress have shorter gate lengths to maintain lower ON-resistance. This localized optimization resolves the contradiction between voltage handling capacity and ON-resistance.
Solution Approach 2:
The patent changes the parameter distribution from uniform to non-uniform, specifically varying gate lengths across the FET stack based on voltage stress conditions. This parameter change allows each FET to be optimized for its specific operating conditions, achieving both high voltage handling capacity and low ON-resistance simultaneously.
2Strength
If a higher stack height is utilized to allow an RF switch to withstand higher power, then voltage handling capacity is improved, but linearity performance deteriorates
Solution Approach 1:
The patent applies local quality by optimizing gate lengths of individual FETs based on their position and voltage stress in the stack. FETs with higher voltage stress have longer gate lengths for improved breakdown voltage and linearity, while FETs with lower stress have shorter gate lengths. This localized optimization maintains excellent linearity performance across the entire stack while achieving high voltage handling capacity.
Solution Approach 2:
The patent changes the gate length parameter distribution to be non-uniform, correlating gate length with voltage stress levels. This parameter optimization ensures that each FET operates in its optimal region, maintaining superior linearity performance while enabling high power handling capability.
3Strength
If FETs are arranged in a stack configuration to handle high power, then voltage handling capacity is improved, but parasitic effects increase
Solution Approach 1:
The patent applies local quality by implementing position-dependent gate length optimization in the FET stack. FETs at different positions in the stack have different gate lengths tailored to their specific voltage stress and parasitic conditions. This localized customization minimizes the impact of parasitic effects while maintaining high voltage handling capacity throughout the stack.
Solution Approach 2:
The patent changes the gate length parameter to vary non-uniformly across the stack, optimizing each FET's electrical characteristics for its specific location and stress conditions. This parameter optimization reduces parasitic effects by ensuring each FET operates efficiently under its local conditions, thereby improving overall stack performance.
Data Source
AI summary
Radio-frequency (RF) switching devices having improved voltage handling capability. In some embodiments, a switching device can include a first terminal and a second terminal, and a plurality of switching elements connected in series to form a stack between the first terminal and the second terminal. The switching elements can have a non-uniform distribution of a parameter that results in the stack having a first voltage handling capacity that is greater than a second voltage handling capacity corresponding to a similar stack having a substantially uniform distribution of the parameter.