III-Nitride Transistor Drain Access Structure for Electric Field Shaping
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Solution Overview
Problem
Conventional III-nitride semiconductor transistors have uniform electron density in the access region between the gate and drain electrodes, limiting their ability to shape the electric field effectively, which restricts their high-current, high-voltage, and high-frequency performance in advanced power electronic devices.
Innovation Solution
The introduction of electron density reduction regions (EDR regions) between the gate and drain electrodes, created through trenches, implantation, or a cap layer, reduces electron density non-uniformly, allowing for localized control of the electric field and charge density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If uniform electron density is maintained in the access region, then device simplicity is preserved, but electric field shaping capability is limited
Solution Approach 1:
The patent introduces electron density reduction regions with different electron densities in specific locations within the access region. These localized modifications create non-uniform electron density distribution, enabling electric field shaping in critical areas while maintaining uniform structure elsewhere, thus achieving adaptability without excessive complexity
Solution Approach 2:
The access region is divided into multiple zones with different electron density characteristics. By segmenting the region and applying different electron density levels to different segments, the patent enables selective electric field control in specific areas while preserving overall structural simplicity
2Reliability
If electron density is reduced in the drain access region, then breakdown voltage is improved, but on-resistance increases
Solution Approach 1:
The patent reduces electron density specifically in the drain access region where high electric fields occur during breakdown, improving reliability. The source access region maintains higher electron density to preserve low on-resistance during normal operation, thus resolving the contradiction through spatially selective electron density control
Solution Approach 2:
The non-uniform electron density distribution creates dynamic electric field control that adapts to different operating conditions. During normal operation, the field distribution minimizes resistance, while during breakdown conditions, the reduced electron density in the drain region enhances voltage blocking capability
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
This non-uniform electron density distribution enhances the control of the electric field and dynamic on-resistance, improving breakdown voltage and performance in high-power electronic devices.
Implementation Method 1
a barrier layer, wherein electrons are formed at an interface between the channel layer and the barrier layer
Implementation Method 2
one or more electron density reduction regions disposed in the drain access region, wherein electron density in the electron density reduction regions is reduced as compared to other portions of the drain access region
Data Source
AI summary
This disclosure describes the structure and technology to modify the free electron density between the gate and drain electrodes of III-nitride semiconductor transistors. Electron density reduction regions (EDR regions) are disposed between the gate and the drain of the transistor structure. In certain embodiments, the EDR regions are created using trenches. In other embodiments, the EDR regions are created by implanting the regions with a species that reduces the free electrons in the channel layer. In another embodiment, the EDR regions are created by forming a cap layer over the barrier layer, wherein the cap layer reduces the free electrons in the channel beneath the cap layer. In another embodiment, a cap layer may be formed in the EDR regions, and doped regions may be created outside of the EDR regions, wherein the impurities act as electron donors.