p-GaN Gate Structure With Local N2 Pre-Treatment for Hump Suppression
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Solution Overview
Problem
Conventional E-mode GaN devices suffer from abnormal hump effects in the Id-Vgs curve, leading to shifts in gate threshold voltage and altered switch properties.
Innovation Solution
Perform N2 pre-treatment on the interface between the AlGaN layer and GaN substrate, using a patterned dielectric mask to confine the treatment to gate and surrounding regions, reducing excess nitrogen ions and maintaining 2DEG channel density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If N2 pre-treatment is performed on the entire AlGaN/GaN interface, then the abnormal hump effect is reduced, but excess nitrogen ions are introduced into non-gate regions causing reduction of 2DEG channel density and increase of channel resistance
Solution Approach 1:
The patent applies N2 pre-treatment selectively only to gate and surrounding regions rather than uniformly across the entire AlGaN/GaN interface. This localized treatment approach uses a patterned dielectric mask to confine nitrogen ion introduction to specific areas, thereby reducing the abnormal hump effect in gate regions without causing excessive nitrogen accumulation in non-gate regions that would reduce 2DEG channel density and increase channel resistance.
2Reliability
If N2 pre-treatment is performed to reduce abnormal hump effect, then gate threshold voltage stability is improved, but channel resistance increases due to excess nitrogen ions in non-gate regions
Solution Approach 1:
The patent implements spatially selective N2 pre-treatment using a patterned dielectric mask that allows nitrogen ion exposure only in gate and surrounding regions. This localized approach stabilizes gate threshold voltage by treating the hump effect in gate regions while preventing excess nitrogen ion accumulation in non-gate regions, thereby avoiding increases in channel resistance and maintaining precise control over channel electrical properties.
3Ease of operation
If conventional E-mode GaN device structure is used, then normally-off characteristic is achieved, but abnormal hump effect occurs in Id-Vgs curve
Solution Approach 1:
The patent applies N2 pre-treatment as a preliminary process step before device fabrication to modify the AlGaN/GaN interface properties in gate regions. This preliminary action reduces the abnormal hump effect in the Id-Vgs curve, thereby stabilizing switch properties and gate threshold voltage while preserving the normally-off characteristic of conventional E-mode GaN devices with p-GaN gates.
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 N2 pre-treatment effectively addresses the abnormal hump effect by minimizing 2DEG channel density fluctuations, enhancing device stability and performance.
Implementation Method 1
the interface between the AlGaN layer and the GaN substrate not covered by the first dielectric layer is subject to a N2 pre-treatment
Data Source
AI summary
A GaN device with N2 pre-treatment is provided in the present invention, including a GaN substrate, an AlGaN layer covering the GaN substrate, a p-GaN gate on the AlGaN layer, a TiN electrode on the p-GaN gate, a first dielectric layer on the AlGaN layer surrounding the p-GaN gate, wherein a horizontal spacing is between the first dielectric layer and the p-GaN gate, and an interface between the AlGaN layer and the GaN substrate not covered by the first dielectric layer is subject to N2 pre-treatment, and a second dielectric layer covering on and directly contacting the exposed first dielectric layer, AlGaN layer, p-GaN gate and TiN electrode.