Patterned III-Nitride HEMT Capping Layer for Trapped Charge Relief
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Solution Overview
Problem
Conventional Group-III-nitride HEMTs suffer from trapped charge at the surface, leading to output-signal distortion and reduced performance in RF transistor amplifiers.
Innovation Solution
Incorporating a patterned Group-III-nitride capping layer with gaps between the source and drain contacts to redistribute charge and compensate for trapped charge, improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous Group-III-nitride capping layer is used on the barrier layer, then the device structure is simple and manufacturing is easy, but trapped charge accumulates at the surface causing output-signal distortion and reduced performance
Solution Approach 1:
The continuous capping layer is divided into segmented regions with gaps between source and drain contacts. This segmentation allows charge redistribution and prevents trapped charge accumulation, thereby improving output-signal quality while maintaining a relatively simple structure.
Solution Approach 2:
The capping layer is configured with different properties in different regions: continuous over the channel for proper device operation, and segmented with gaps over the contact regions to enable charge redistribution. This local differentiation addresses the trapped charge problem without compromising overall device functionality.
2Reliability
If the capping layer is separated from contacts to redistribute charge, then transient behavior improves, but manufacturing precision requirements increase
Solution Approach 1:
Instead of completely separating the capping layer from all contacts, the invention applies partial separation only in specific regions (gaps between source and drain contacts). This partial action achieves the necessary charge redistribution for improved transient behavior while avoiding the need for complete precision separation that would be required if the entire capping layer were detached.
Data Source
AI summary
Group-III-nitride high-electron-mobility transistors (HEMTs) are provided. A Group-III-nitride HEMT includes a substrate. The Group-III-nitride HEMT includes a barrier layer on the substrate. The Group-III-nitride HEMT includes a source contact and a drain contact that are on the barrier layer. Moreover, the Group-III-nitride HEMT includes a Group-III-nitride capping layer on the barrier layer and separated from the drain contact by a gap.