Group-III Nitride Semiconductor Device With Silicon Oxynitride Passivation
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Solution Overview
Problem
Existing high-voltage and low-leakage group-III nitride semiconductor devices face trade-offs between forward current and reverse breakdown voltage, and suffer from current collapse and surface leakage issues, which hinder high-speed operation and device performance.
Innovation Solution
A semiconductor stack structure comprising a Ga-face AlGaN/GaN epitaxial structure with a substrate, buffer layers, and a passivation film of silicon oxynitride is used, optimizing the device for high reverse breakdown voltage, high forward current, and low surface leakage current, while allowing for fast forward recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the spacing between electrodes is shortened, then the forward current is increased, but the reverse breakdown voltage is lowered
Solution Approach 1:
The device is segmented into two functional regions: a first region with a first breakdown voltage and a second region with a second breakdown voltage. This segmentation allows each region to be optimized independently, with the first region providing high forward current and the second region providing high reverse breakdown voltage, thereby resolving the contradiction between forward current and reverse breakdown voltage.
Solution Approach 2:
Different regions of the device are given different local properties: the first region is designed with characteristics optimized for forward current conduction, while the second region is designed with characteristics optimized for reverse breakdown voltage. This local differentiation allows simultaneous achievement of high forward current and high reverse breakdown voltage.
2Reliability
If SiO2 is used as the surface passivation film, then the breakdown voltage is increased, but the forward recovery current is slowed down
Solution Approach 1:
The surface passivation film is formed as a composite structure comprising a first passivation film and a second passivation film with different material compositions and properties. The first passivation film provides high breakdown voltage, while the second passivation film enables fast forward recovery current, thereby resolving the contradiction between breakdown voltage and forward recovery speed.
Solution Approach 2:
The passivation film is segmented into multiple layers with different functions: the first passivation film layer provides electrical insulation and breakdown voltage, while the second passivation film layer provides surface passivation and enables fast recovery current. This functional segmentation resolves the contradiction between breakdown voltage and recovery speed.
3Reliability
If HEMT is coupled to SBD, then the reverse breakdown voltage is increased, but the device area and switching speed are reduced
Solution Approach 1:
The invention merges the functions of HEMT and SBD into a single integrated device structure. The first region functions as a diode for rectification while the second region provides voltage blocking capability, combining the advantages of both HEMT and SBD in one device, thereby achieving high reverse breakdown voltage without requiring separate coupled devices and reducing overall device area.
Solution Approach 2:
The integrated device structure performs multiple functions: the first region provides forward current conduction and rectification, while the second region provides reverse breakdown voltage blocking. This multi-functional design eliminates the need for separate HEMT and SBD components, reducing device area while maintaining high reverse breakdown voltage.
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 solution enables the formation of high-voltage and high-speed active devices with improved reverse breakdown voltage, forward current, and reduced surface leakage current, enhancing device reliability and performance under high-speed operations.
Implementation Method 1
a passivation film of silicon oxynitride is used, optimizing the device for high reverse breakdown voltage, high forward current, and low surface leakage current
Data Source
AI summary
The present application discloses a group-III nitride semiconductor device, which comprises a substrate, a buffer layer, a semiconductor stack structure, and a passivation film. The buffer layer is disposed on the substrate. The semiconductor stack structure is disposed on the buffer layer and comprises a gate, a source, and a drain. In addition, a gate insulating layer is disposed between the gate and the semiconductor stack structure for forming a HEMT. The passivation film covers the HEMT and includes a plurality of openings corresponding to the gate, the source, and the drain, respectively. The material of the passivation film is silicon oxynitride.