Nitride Transistor Structure With Built-In PN Discharge Path
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Solution Overview
Problem
Conventional nitride semiconductor transistors face breakdown issues due to high source-drain voltage, leading to permanent failure and increased manufacturing costs due to larger device size.
Innovation Solution
A nitride semiconductor transistor structure is designed with a substrate structure comprising a heavily doped P-type substrate and a lightly doped P-type epitaxial layer, forming an N-type region and a PN-type diode. This structure includes a nitride epitaxial layer and functional electrode layers, with a metal connector providing a discharge channel for current during high voltage conditions, preventing breakdown without increasing gate-drain spacing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gate-drain spacing is increased to prevent transistor breakdown, then reliability is improved, but device area increases
Solution Approach 1:
The invention segments the drain structure into multiple parts: a first drain region, a second drain region, and a third drain region. The first drain region is positioned closer to the gate with a smaller area, while the second and third drain regions are positioned farther away. This segmentation allows the drain to handle high voltage stress without requiring increased gate-drain spacing, thus preventing breakdown while maintaining compact device area.
Solution Approach 2:
The invention applies local quality by creating regions with different doping concentrations and geometries within the drain structure. The first drain region has different properties than the second and third drain regions, allowing each region to perform its specific function optimally. This local differentiation enables breakdown prevention without increasing overall device area.
2Reliability
If gate-drain spacing is increased to ensure voltage withstanding, then breakdown protection is improved, but manufacturing cost increases
Solution Approach 1:
By segmenting the drain into multiple regions with different positions and areas, the invention achieves voltage withstanding capability without increasing gate-drain spacing. This maintains device density and reduces manufacturing costs associated with larger device footprints.
3Reliability
If a discharge channel is provided for current during high voltage conditions, then device reliability is improved, but device complexity increases
Solution Approach 1:
The invention merges the discharge channel function directly into the drain structure by creating the segmented drain regions. The first drain region acts as the discharge path for current during high voltage conditions. This integration avoids adding separate protection structures, thereby improving reliability while minimizing increases in device complexity.
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 proposed structure enhances the voltage withstanding capability of the transistor, improves device reliability by providing a discharge channel for current, and reduces manufacturing costs by maintaining device density without increasing gate-drain spacing.
Implementation Method 1
the heavily doped P-type substrate and the lightly doped P-type epitaxial layer enable a current to present unidirectional conductivity of being conducted in one direction from the heavily doped P-type substrate to the lightly doped P-type epitaxial layer
Implementation Method 2
a metal connector is formed in the first isolation portion, and the metal connector penetrates through the first isolation portion to connect the drain and the N-type region
Data Source
Figure 1~3
Figure 4~5c
Figure 5d~5f
AI summary
This application provides a nitride semiconductor transistor and an electronic device. The nitride semiconductor transistor includes a substrate structure, a nitride epitaxial structure, and a functional electrode layer. The substrate structure includes a heavily doped P-type substrate and a lightly doped P-type epitaxial layer that are disposed through stacking, and a side that is of the lightly doped P-type epitaxial layer and that is away from the heavily doped P-type substrate extends towards the heavily doped P-type substrate to form an N-type region. The nitride epitaxial structure includes a nitride buffer layer, a barrier layer, and a P-type nitride layer that are successively formed on the lightly doped P-type epitaxial layer. The functional electrode layer includes a source, a drain, a gate, and an isolation layer, and a first isolation portion corresponds to the N-type region and penetrates through the barrier layer and the nitride buffer layer to be in contact with the lightly doped P-type epitaxial layer. A metal connector is formed in the first isolation portion, and the metal connector penetrates through the first isolation portion to connect the drain and the N-type region. The nitride semiconductor transistor is equivalent to a built-in PN-type diode, and forms a current discharge channel, to improve device reliability.