GaN HEMT with FexNy Interlayers for Leakage Reduction
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Solution Overview
Problem
Current GaN Heterojunction Field Effect Transistor (HFET) devices face challenges in reducing leakage current and maximizing breakdown voltage, which are critical for reliable high-temperature and high-frequency applications, especially in hybrid vehicle semiconductor switches.
Innovation Solution
The solution involves forming a semiconductor device with a first GaN layer comprising multiple GaN layers and FexNy layers interposed between them, where the FexNy layers are inserted to reduce crystal defects and leakage current, and using a p-type dopant like Fe to enhance the semi-insulating function and trap formation, while optimizing growth conditions to minimize warpage and cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer GaN structure is used, then the device structure is simple, but the leakage current is high and breakdown voltage is low
Solution Approach 1:
The first GaN layer is segmented into multiple sub-layers (first, second, third GaN layers) with different thicknesses and doping configurations. Each sub-layer serves a specific function: the first GaN layer provides mechanical support, the second GaN layer forms the active channel region, and the third GaN layer reduces dislocation density. This segmentation allows optimization of each layer's properties to simultaneously reduce leakage current and increase breakdown voltage while maintaining manufacturability.
Solution Approach 2:
Different regions of the GaN layer are assigned different local properties through selective doping. The first GaN layer is doped with Si to provide high electron concentration for low on-resistance, while the third GaN layer is doped with Mg to reduce dislocation density and improve breakdown characteristics. This local quality differentiation enables simultaneous optimization of conductivity and breakdown voltage without requiring complete structural redesign.
2Reliability
If multiple GaN layers with FexNy interlayers are formed, then leakage current is reduced and breakdown voltage is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
FexNy interlayers are formed preliminarily between the GaN layers during the epitaxial growth process, before subsequent device fabrication steps. This preliminary formation of interlayers with specific magnetic and electrical properties prevents dislocation propagation and reduces leakage current in advance, simplifying later manufacturing steps by eliminating the need for additional defect-reduction processes.
Solution Approach 2:
The device employs a composite structure combining GaN layers with FexNy interlayers. The FexNy material provides unique properties including high saturation magnetization and semi-metallic characteristics that suppress leakage current through spin-dependent scattering mechanisms. This composite material approach achieves superior electrical performance while maintaining compatibility with existing GaN fabrication processes.
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 approach effectively reduces leakage current and enhances the breakdown voltage, enabling the fabrication of high-power HFET devices with improved reliability and performance at high temperatures.
Implementation Method 1
forming a first GaN layer including a plurality of GaN layers and FexNy layers interposed between the plurality of GaN layers
Implementation Method 2
using a p-type dopant like Fe to enhance the semi-insulating function and trap formation
Data Source
AI summary
This specification is directed to a semiconductor device capable of reducing a leakage current by forming a first GaN layer including a plurality of GaN layers and FexNy layers interposed between the plurality of GaN layers, in a semiconductor device having the first GaN layer, an AlGaN layer, a second GaN layer, a gate electrode, a source electrode and a drain electrode which are deposited in a sequential manner, and a fabricating method thereof.To this end, a semiconductor device according to one exemplary embodiment includes a first GaN layer, an AlGaN layer on the first GaN layer, a second GaN layer on the AlGaN layer, and a source electrode, a drain electrode and a gate electrode formed on a portion of the second GaN layer, wherein the first GaN layer comprises a plurality of GaN layers and FexNy layers interposed between the plurality of GaN layers.