GaN HEMT Asymmetric Field Plates for Drain Electric Field Control
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Solution Overview
Problem
Conventional high electron mobility transistors (HEMTs) face challenges in achieving optimal breakdown voltage and electric field distribution due to the traditional design where the length of the source field plate is often equal to or larger than the drain field plate, leading to reduced reliability and breakdown voltage.
Innovation Solution
A high electron mobility transistor design where the length of the drain field plate is greater than the source field plate, with the field plate situated between the gate and drain electrode metals, optimizing the breakdown voltage and electric field distribution by ensuring a more uniform electric field and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the source field plate length is equal to or larger than the drain field plate length (conventional design), then the device structure is simpler and easier to manufacture, but the breakdown voltage is reduced and electric field distribution is non-uniform
Solution Approach 1:
The patent applies asymmetry by making the drain field plate length (Ldf) greater than the source field plate length (Lsf). This asymmetric configuration optimizes the electric field distribution specifically in the drain region where high electric field stress occurs during operation, thereby increasing breakdown voltage and improving reliability without significantly complicating the manufacturing process
2Ease of manufacture
If the source field plate length is equal to or larger than the drain field plate length (conventional design), then the manufacturing process is simpler, but the electric field distribution becomes non-uniform leading to increased drain leakage
Solution Approach 1:
The asymmetric field plate design with Ldf > Lsf creates a more uniform electric field distribution across the device. The extended drain field plate specifically addresses the high electric field concentration at the drain edge, reducing field-induced leakage currents while maintaining manufacturing feasibility through standard lithography processes
3Reliability
If the drain field plate length is made larger than the source field plate length, then the breakdown voltage increases and electric field uniformity improves, but the device complexity increases
Solution Approach 1:
The patent applies local quality by extending the field plate length specifically in the drain region (Ldf > Lsf) where it is most needed to manage high electric field stress. This localized modification targets the critical area without unnecessarily complicating the entire device structure, maintaining relative simplicity while achieving improved breakdown voltage and electric field uniformity
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 design enhances the breakdown voltage and uniformity of the electric field, resulting in improved reliability and reduced drain leakage, with simulations showing a reduction in electric field at the drain electrode by over 20% compared to conventional designs.
Implementation Method 1
at least one metal field plate is commonly used in a power device, especially in a high electron mobility transistor (HEMT) device, to re-shape the electric field within the device. As a result, the peak electric field inside the device can be reduced, the breakdown voltage (BV) of the high electron mobility transistor can be increased
Data Source
AI summary
A high electron mobility transistor (HEMT) includes a GaN epi-layer, a first passivation layer, a source electrode metal, a drain electrode metal, a gate electrode metal, and a field plate. The first passivation layer is deposited on the GaN epi-layer. The source electrode metal, the drain electrode metal, and the gate electrode are recessed into the first passivation layer and deposited on the GaN epi-layer. The source electrode metal has a source field plate with a source field plate length Lsf. The drain electrode metal has a drain field plate with a drain field plate length Ldf, wherein Ldf>Lsf. The gate electrode is situated between the source electrode metal and the drain electrode metal. The field plate is situated between the gate electrode and the drain electrode metal.