Nitride Semiconductor Device With Backside Voids
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Solution Overview
Problem
Nitride semiconductor devices face issues with excessive defects due to lattice and thermal expansion mismatches, leading to decreased breakdown voltage and current collapse under varying bias conditions.
Innovation Solution
A nitride semiconductor device design featuring a substrate with voids and a metal layer on its back surface, along with a dielectric layer and insulation doped regions, to reduce electric fields and enhance breakdown voltage, and a channel layer structure including nucleation, buffer, and barrier layers to minimize current leakage and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an epitaxial layer is grown on a silicon substrate, then the device can be manufactured, but excessive defects occur due to lattice mismatch and thermal expansion coefficient difference, resulting in decreased breakdown voltage
Solution Approach 1:
A buffer layer is introduced as an intermediary between the silicon substrate and the GaN epitaxial layer. This buffer layer mediates the lattice mismatch and thermal expansion coefficient difference, reducing defect formation while enabling the epitaxial growth to proceed. The buffer layer acts as a transition zone that gradually adapts the crystal structure from silicon to GaN, thereby maintaining both manufacturability and device reliability.
2Adaptability or versatility
If the device operates under varying bias voltage conditions, then the device functionality is maintained, but internal defects trap or release electrons leading to changing on-resistance and current collapse
Solution Approach 1:
Defect regions are extracted or removed from the active device structure through selective etching or growth of sacrificial layers. By taking out the defect-prone regions before final device formation, the source of electron trapping and on-resistance variation is eliminated, preventing current collapse while maintaining operational adaptability across bias voltage conditions.
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 design increases breakdown voltage, reduces current collapse, and improves heat conduction, effectively addressing defects and operational efficiency.
Implementation Method 1
a back substrate structure including at least one void (e.g., a first void and an optional second void) and a metal layer is introduced to a nitride semiconductor device, so as to increase the breakdown voltage and reduce current collapse
Data Source
AI summary
Provided is a nitride semiconductor device including a substrate, a nucleation layer, a buffer layer, a channel layer, a first electrode, and a second electrode. The substrate has a first surface and a second surface opposite to the first surface. The nucleation layer, the buffer layer, the channel layer, and the barrier layer are sequentially disposed on the first surface of the substrate. The first electrode layer and the second electrode layer are disposed on the barrier layer. A first void penetrates through the substrate, the nucleation layer, the buffer layer, the channel layer, and the barrier layer and exposes a portion of the first electrode.