GaN HEMT Strain-Compensating Layer for Breakdown Suppression
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Solution Overview
Problem
High electron mobility transistors (HEMTs) face challenges in yield rate and performance, particularly due to breakdown and hot electron issues, which affect their suitability for mass production and high-power/high-frequency applications.
Innovation Solution
A nitride-based semiconductor device with a strain-compensating layer of varying thickness is introduced, where the strain-compensating layer is positioned between the gate and drain electrodes, allowing for a gradually increasing two-dimensional electron gas (2DEG) density to address breakdown and hot electron issues, thereby enhancing the performance of GaN-based HEMT devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform thickness strain-compensating layer is used, then the manufacturing process is simple, but the 2DEG density cannot be effectively increased to resolve breakdown and hot electron issues
Solution Approach 1:
The strain-compensating layer transitions from uniform thickness to non-uniform thickness, where the thickness varies in the lateral direction. Specifically, the layer has a first thickness in a first region and a second thickness in a second region, with the second thickness being greater than the first. This local variation in thickness creates corresponding variations in 2DEG density, allowing higher 2DEG density in regions where it is needed to mitigate breakdown and hot electron effects, while maintaining lower thickness in other regions.
2Reliability
If the 2DEG density is increased to improve performance, then breakdown and hot electron issues are reduced, but the device complexity increases
Solution Approach 1:
The invention changes the thickness parameter of the strain-compensating layer from a constant value to a variable value that changes in the lateral direction. This parameter variation creates corresponding variations in strain distribution and 2DEG density across different regions of the device. By carefully controlling the thickness profile, the invention achieves higher 2DEG density in specific regions to improve performance and reduce breakdown and hot electron issues, while the complexity is managed through a systematic approach to layer design.
3Reliability
If a varying thickness strain-compensating layer is implemented, then 2DEG density is effectively increased, but the manufacturing precision requirements increase
Solution Approach 1:
The strain-compensating layer is designed with dynamic thickness characteristics, transitioning from a static uniform thickness to a dynamic profile that varies in the lateral direction. The layer has different thicknesses in different regions, creating a graded structure that allows for controlled variation in 2DEG density. This dynamic design enables precise control over carrier distribution by adjusting the thickness profile, thereby improving reliability while managing manufacturing precision requirements through a systematic approach to non-uniform layer formation.
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 varying thickness of the strain-compensating layer effectively increases 2DEG density, improving the performance of GaN-based HEMT devices by reducing breakdown and hot electron issues, thus enhancing the yield rate and making them more suitable for mass production.
Implementation Method 1
a strain-compensating layer with a varying thickness for improving the performance of the HEMT
Implementation Method 2
The HEMT utilizes a heterojunction interface between two materials with different bandgaps to form a quantum well-like structure, which accommodates a two-dimensional electron gas (2DEG) region
Data Source
AI summary
A nitride-based semiconductor device includes a first nitride-based semiconductor layer, a second nitride-based semiconductor layer, a source electrode, a drain electrode, a gate electrode a first strain-compensating layer, and a first protection layer. The second nitride-based semiconductor layer is disposed on the first nitride-based semiconductor layer and has a bandgap greater than a bandgap of the first nitride-based semiconductor layer. The source electrode and the drain electrode are disposed above the second nitride-based semiconductor layer. The gate electrode is disposed between the source and drain electrodes. The first strain-compensating layer is disposed above the second nitride-based semiconductor layer and between the drain and gate electrodes. The first protection layer covers the first strain-compensating layer to form a first interface, in which a vertical distance between the first interface and the second nitride-based semiconductor layer increases along a direction pointing toward the drain electrode from the gate electrode.