GaN Heterojunction Diode with Schottky Barrier Junction
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Solution Overview
Problem
Conventional GaN-based diodes face challenges in achieving low on-resistance and high-speed switching due to high access resistance and capacitance issues, particularly with the Schottky electrode junction and parallel-plate capacitor formation.
Innovation Solution
The semiconductor device employs a Schottky barrier junction formed at the end faces of the AlGaN and GaN layers, with recesses extending to the nitride semiconductor layer, allowing direct contact and minimizing capacitance, thereby reducing on-resistance and capacitance, and incorporating a substrate with through holes for improved heat dissipation and reduced parasitic inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple heterojunctions are used to increase two-dimensional electron gas concentration, then the on-resistance can be reduced, but the device complexity increases
Solution Approach 1:
The patent utilizes the vertical dimension to stack multiple heterojunctions, allowing multiple two-dimensional electron gas channels to be accessed vertically rather than requiring lateral expansion. This vertical stacking achieves low on-resistance through multiple parallel conduction paths while maintaining compact device footprint and manageable structural 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
This structure enables a semiconductor device with extremely low loss and high-speed operation, achieving both low resistance and high breakdown voltage characteristics, suitable for high-power applications.
Implementation Method 1
a Schottky electrode that is placed at a first end of the stack structure and forms a Schottky barrier contact with the one or more heterojunction units
Implementation Method 2
an ohmic electrode that is placed at a second end of the stack structure and forms an ohmic contact with the one or more heterojunction units
Implementation Method 3
each of the one or more heterojunction units being a stack of a layer made of a nitride semiconductor and a layer made of another nitride semiconductor having a larger band gap than the nitride semiconductor
Data Source
AI summary
To provide a semiconductor device that has a sufficiently low on-resistance and excellent low-capacitance and high-speed characteristics as compared with conventional GaN-based diodes. The semiconductor device includes: a substrate (101); a buffer layer (102); a stack structure (103 and 104) including at least one heterojunction unit (103 and 104) that is a stack of a layer (GaN layer 103) made of a nitride semiconductor and a layer (AlGaN layer 104) made of another nitride semiconductor having a larger band gap than the nitride semiconductor (GaN layer 103); a Schottky electrode (106) that is placed at a first end of the stack structure (103 and 104) and forms a Schottky barrier contact with the heterojunction unit (103 and 104); and an ohmic electrode (107) that is placed at a second end of the stack structure (103 and 104) and forms an ohmic contact with the heterojunction unit (103 and 104).