Nitride Semiconductor Protrusion for Surge Current
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Solution Overview
Problem
Conventional nitride semiconductor devices with a Schottky barrier diode structure struggle to achieve a high peak forward surge current while maintaining low forward voltage and high reverse breakdown voltage due to insufficient light diffusion from the pn junction region, resulting from the obstacle created by the lateral surface of the protrusion.
Innovation Solution
A nitride semiconductor device is designed with a substrate and nitride semiconductor layers of different conductivity types, where the second nitride semiconductor layer is formed on a protrusion with an inclined lateral surface, allowing for increased light diffusion and reduced on-resistance through the photoconductive effect, thereby enhancing the peak forward surge current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional Schottky barrier diode structure with a planar pn junction is used, then the device can achieve low forward voltage and high reverse breakdown voltage, but the peak forward surge current cannot be increased enough due to insufficient light diffusion
Solution Approach 1:
The patent applies curvature by forming a protrusion with an inclined lateral surface instead of a planar structure. This curved/angled surface geometry enables light emitted from the pn junction to diffuse more effectively through the semiconductor layer, converting the harmful obstruction into a beneficial light-guiding structure that enhances peak forward surge current
2Reliability
If the lateral surface of the protrusion is made vertical to simplify manufacturing, then the structure is easier to fabricate, but light diffusion is blocked and peak forward surge current cannot be increased
Solution Approach 1:
The patent changes the geometric parameter of the lateral surface from vertical (90 degrees) to an inclined angle. This parameter modification allows light to propagate through the protrusion structure rather than being blocked, thereby enhancing light diffusion and increasing peak forward surge current while maintaining manufacturability
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 device achieves a high reverse breakdown voltage, low forward voltage, and increased peak forward surge current by optimizing light diffusion and reducing on-resistance, improving its performance compared to conventional structures.
Implementation Method 1
allowing for increased light diffusion and reduced on-resistance through the photoconductive effect
Data Source
AI summary
A nitride semiconductor device includes: a substrate having a first major surface and a second major surface; a first nitride semiconductor layer of an n-type which is disposed on the first major surface and has a protrusion; a second nitride semiconductor layer of a p-type disposed on the protrusion; a first anode electrode disposed above the first nitride semiconductor layer and the second nitride semiconductor layer; and a cathode electrode disposed under the second major surface, and a lateral surface of the protrusion is inclined by a first angle with respect to the first major surface.