Gate and Drain Interconnect Layout for Wide RF Transistor Fingers
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Solution Overview
Problem
High power, high frequency transistors face challenges in maintaining performance due to increased gate finger widths, which lead to higher resistance and phase differences in signal propagation, affecting output power and efficiency.
Innovation Solution
The transistor design includes a semiconductor structure with gate and drain fingers that are fed at interior positions of interconnects, allowing for parallel operation of segments, reducing phase differences and maintaining lower resistance, thereby enhancing gain and output power without increasing physical dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If gate fingers are made wider to increase output power, then the gate periphery is increased, but the high frequency performance is adversely impacted and electromigration occurs
Solution Approach 1:
The gate interconnect is divided into multiple segments with signal feed points at interior positions rather than ends. This segmentation allows the gate finger to be effectively divided into parallel current paths, reducing the effective current path length and maintaining high frequency performance while supporting wider gate fingers for increased power output.
Solution Approach 2:
The patent introduces a new dimensional approach by feeding the gate interconnect at interior positions along its length rather than only at the ends. This changes the signal distribution pattern from a linear end-to-end approach to a multi-point distribution along the interconnect dimension, reducing phase differences and effective resistance.
2Power
If gate fingers are made wider to increase current handling, then the gate periphery is increased, but electromigration of the gate finger metallization occurs
Solution Approach 1:
By segmenting the gate interconnect into multiple sections with feed points at interior positions, the current path is effectively divided into parallel segments. This reduces the current density in any single path, preventing electromigration even when the overall gate finger width is increased to handle higher total current.
Solution Approach 2:
The patent applies different electrical characteristics to different portions of the gate interconnect by introducing multiple feed points at specific interior positions. This creates local variations in current distribution that optimize the overall current handling capability while preventing localized overheating and electromigration.
3Power
If gate fingers are made wider to increase gate periphery, then the resistance increases and phase differences increase, but the patent seeks to maintain lower resistance
Solution Approach 1:
The gate interconnect is segmented into multiple sections with feed points distributed along its length. This segmentation creates multiple parallel current paths that reduce the effective resistance, allowing wider gate fingers to be used without proportionally increasing the overall resistance and energy loss.
Solution Approach 2:
By changing the signal feed configuration from end-point only to interior positions along the interconnect dimension, the patent creates a multi-dimensional current distribution pattern that reduces the effective current path length and associated resistance, even as the gate periphery increases.
Data Source
AI summary
Pursuant to some embodiments of the present invention, transistor devices are provided that include a semiconductor structure, a drain finger extending on the semiconductor structure in a first direction, and a drain interconnect extending in the first direction and configured to be coupled to a drain signal at an interior position of the drain interconnect, where the drain interconnect is connected to the drain finger at a position offset from the interior position of the drain interconnect.