Voltage-Resistant Transistor Arrangement for RF Power Amplifiers
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Solution Overview
Problem
Modern CMOS technologies face challenges in producing radio-frequency output powers required for wireless communication due to low-voltage transistor technologies, where conventional silicon technologies lack the necessary dielectric strength for power amplifiers, particularly for mobile radio applications, with breakdown voltage limitations from pn junctions and oxide breakdown.
Innovation Solution
The implementation of voltage-resistant transistor arrangements, such as electronic cascode circuits with specific configurations of transistors and capacitors, which manage low breakdown voltage strengths with minimal additional technological or circuitry expenditure, allowing for higher supply voltages and output powers in CMOS, BiCMOS, and SiGe technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional silicon technologies are used with low-voltage transistor technologies, then manufacturing complexity is reduced, but dielectric strength and breakdown voltage are insufficient for required radio-frequency output powers
Solution Approach 1:
The patent divides the transistor structure into multiple segments by stacking transistors in series, where each transistor handles a portion of the total voltage. This segmentation allows the system to achieve high breakdown voltage capability using individual low-breakdown-voltage transistors, resolving the contradiction between dielectric strength requirements and manufacturing simplicity.
Solution Approach 2:
The patent implements nested transistor structures where transistors are stacked vertically with source/drain regions of one transistor formed within or adjacent to another transistor's structure. This nesting approach achieves high voltage capability through multiple stacked devices while minimizing additional manufacturing complexity by sharing common structures.
2Strength
If stacked transistor arrangements are used to increase breakdown voltage, then dielectric strength is improved, but the number of stacked transistors is limited by pn junction breakdown voltage
Solution Approach 1:
The patent introduces intermediate potential structures, such as lightly-doped drain regions and potential wells, between stacked transistors to distribute and manage voltage distribution. These intermediary structures prevent excessive voltage concentration at any single pn junction, enabling more transistors to be stacked beyond what would be possible with conventional direct stacking.
Solution Approach 2:
The patent applies different doping concentrations and material compositions at specific locations within the stacked transistor structure. By creating local variations in dielectric strength and breakdown characteristics through selective doping (e.g., lightly-doped drain regions) and material selection, the structure optimizes voltage distribution across each transistor to maximize the total stack height.
3Power
If higher supply voltages are applied to achieve required output powers, then radio-frequency output power is improved, but oxide breakdown and pn junction breakdown occur
Solution Approach 1:
The patent segments the high supply voltage across multiple stacked transistors, so each individual transistor experiences only a fraction of the total voltage. This voltage segmentation prevents oxide breakdown in any single transistor while collectively achieving the required high output power through the series-connected structure.
Solution Approach 2:
The patent modifies physical parameters such as doping concentrations, junction depths, and material compositions to optimize breakdown characteristics. By changing these parameters locally within the stacked structure, the patent enhances oxide and pn junction breakdown resistance while maintaining the ability to operate at high supply voltages for required output power.
Data Source
AI summary
In accordance with one exemplary embodiment, an electronic circuit is provided, wherein the electronic circuit comprises a first transistor and also a second transistor coupled in series with the first transistor. Furthermore, the electronic circuit comprises a capacitor, wherein a first terminal of the capacitor is coupled to a control terminal of the second transistor, and wherein a second terminal of the capacitor is coupled to an electrical potential which is dependent on a radio-frequency input signal of the electronic circuit.