MMIC Gate Jumper Segmentation for Power and Reliability

Solution Overview

Problem

High power, high frequency transistors face challenges in maintaining high frequency performance and reliability due to increased current densities and electromigration issues associated with wider gate fingers, which can lead to instability and reduced gain.

Innovation Solution

The implementation of a transistor design with segmented gate fingers and a gate jumper system that distributes the gate signal across multiple points along the gate finger, reducing current density and incorporating series and odd mode resistors to stabilize feedback loops, thereby enhancing reliability and frequency performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If gate fingers are made wider to increase output power, then power handling capability is improved, but high frequency performance deteriorates and electromigration occurs

Engineering Contradiction:

Improveoutput powerVSAvoidhigh frequency performance

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The gate finger is divided into multiple segments along its length, with each segment independently connected to the gate pad through gate jumpers. This segmentation reduces the current density in each individual segment while maintaining the total gate periphery width needed for high power handling, thereby preventing electromigration and maintaining high frequency performance.

Inventive Principle:

Principle #1Segmentation

2Power

If gate fingers are made wider to increase output power, then power handling capability is improved, but current density increases causing electromigration

Engineering Contradiction:

Improveoutput powerVSAvoidelectromigration

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The gate finger is divided into multiple segments along its length, with each segment independently connected to the gate pad through gate jumpers. This segmentation reduces the current density in each individual segment while maintaining the total gate periphery width needed for high power handling, thereby preventing electromigration and maintaining high frequency performance.

Inventive Principle:

Principle #1Segmentation

3Power

If multiple gate fingers are added in parallel to increase output power, then power handling capability is improved, but device complexity increases

Engineering Contradiction:

Improveoutput powerVSAvoidtransistor structure complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

Multiple gate finger segments are electrically connected in parallel through gate jumpers to form a unified gate structure. This merging approach achieves the desired power handling capability through increased effective gate periphery while managing complexity by using a systematic jumper connection pattern rather than completely independent gate structures.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9947616B2High power MMIC devices having bypassed gate transistors

Publication Date: 2018.04.17 MACOM TECH SOLUTIONS HLDG INC

AI summary

Monolithic microwave integrated circuits are provided that include a substrate having a transistor and at least one additional circuit formed thereon. The transistor includes a drain contact extending in a first direction, a source contact extending in the first direction in parallel to the drain contact, a gate finger extending in the first direction between the source contact and the drain contact and a gate jumper extending in the first direction. The gate jumper conductively connects to the gate finger at two or more locations that are spaced apart from each other along the first direction.