GaN Gate Field Plate Layout for Lower Gate-Drain Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
GaN transistors face issues with gate-edge electric fields that lead to charge trapping and degradation, and conventional methods to mitigate these fields increase the gate-to-drain capacitance ratio, degrading performance.
Innovation Solution
Incorporating a gate-connected field plate that extends towards the drain region and an integrated gate-to-source capacitance to mitigate electric fields, while maintaining a balanced capacitance ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to mitigate gate-edge electric fields, then reliability is improved, but gate-to-drain capacitance ratio increases degrading performance
Solution Approach 1:
The field plate extends in a lateral dimension beyond the gate edge, creating a three-dimensional structure that redistributes electric fields in space. This dimensional extension allows the field plate to mitigate gate-edge effects without increasing capacitance, as the extended structure creates a more gradual field distribution in the vertical and lateral dimensions simultaneously.
Solution Approach 2:
The field plate is positioned specifically at the gate-edge region where electric field concentration occurs, providing localized mitigation. The field plate's electrical connection to the gate creates a localized field redistribution effect precisely where needed, without affecting other regions of the device that would contribute to unwanted capacitance.
2Reliability
If gate-connected field plate is used to reduce gate-edge electric fields, then reliability is improved, but device complexity increases
Solution Approach 1:
The field plate is electrically connected to the gate, merging their functions into a single integrated structure. This connection allows the field plate to operate as an extension of the gate, providing field mitigation while being controlled by the same gate voltage, thereby reducing the need for separate control circuits and reducing overall device complexity.
Solution Approach 2:
The field plate serves multiple functions: it mitigates gate-edge electric fields, extends the gate's electric field control region, and maintains electrical connection with the gate for unified control. This multi-functionality reduces the need for additional separate components, thereby reducing device complexity while improving reliability.
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 effectively reduces gate-edge electric field effects, improves reliability, and maintains performance by reducing the gate-to-drain capacitance ratio, enhancing switching speed and breakdown voltage.
Implementation Method 1
a dielectric layer disposed on the GaN-based layer and having a second thickness that is less the first thickness, where the dielectric layer is in contact with the P-type GaN layer
Implementation Method 2
a field plate disposed on the dielectric layer and positioned between the P-type GaN layer and the drain region, where the field plate is connected to the source electrode
Implementation Method 3
This structure is known to form a high electron mobility two-dimensional electron gas (2DEG) at the junction
Data Source
AI summary
A device is disclosed. The device includes a gallium nitride (GaN)-based substrate including a two-dimensional electron gas (2DEG) layer, a source region including a source electrode, a drain region separate from the source region, a gate region disposed between the source region and the drain region, the gate region including a P-type GaN layer and a gate electrode disposed on a top surface of the P-type GaN layer, wherein the gate electrode extends from a first edge to a second edge; and a field plate electrically coupled to the gate electrode at a junction. In one aspect, the field plate extends from the junction towards the source region, beyond the first edge, to a first distal end that is proximate the source electrode. In another aspect, the field plate extends from the junction towards the drain region, beyond the second edge, to a second distal end.