In-Situ Oxide Passivation for III-Nitride HEMTs
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Solution Overview
Problem
Current oxide deposition for GaN/AlGaN based high electron mobility transistors requires multiple tools, increasing costs and resulting in high interfacial charge density, which degrades device performance.
Innovation Solution
In-situ metal-organic chemical vapor phase epitaxy using nitrogen as a carrier gas for single-step deposition of metal oxide semiconductor heterojunction field effect transistors, reducing interfacial charge density and trap density by integrating III-Nitride and III-Oxide technology in the same reactor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If oxide deposition is performed using multiple different deposition tools, then the fabrication process can be completed with existing separate tools, but the per unit cost increases and interfacial charge density becomes high
Solution Approach 1:
The patent combines separate oxide deposition and nitride semiconductor fabrication processes into a single integrated reactor system. This allows both processes to be performed in the same vacuum chamber without breaking vacuum, eliminating the need for multiple deposition tools and reducing interfacial charge density at the oxide-nitride interface.
Solution Approach 2:
The reactor is designed with multi-functionality to perform both nitride semiconductor epitaxial growth and oxide deposition tasks. By using a universal reactor that can accommodate different gas chemistries and deposition conditions, the system eliminates tool dependency while maintaining process quality.
2Adaptability or versatility
If oxide deposition is performed using multiple different deposition tools, then existing tools can be utilized, but the fabrication process complexity increases
Solution Approach 1:
The patent merges multiple deposition functions into a single reactor system, reducing fabrication process complexity. The integrated approach eliminates the need for multiple tool transitions, process interruptions, and associated alignment steps, thereby simplifying the overall fabrication workflow.
3Adaptability or versatility
If separate deposition tools are used for oxide deposition, then process flexibility is maintained, but interfacial charge density increases
Solution Approach 1:
The patent combines oxide and nitride deposition in a single vacuum environment, eliminating exposure to air and contaminants at the interface. This integrated approach maintains process flexibility while dramatically reducing interfacial charge density by preventing contamination and ensuring clean interfaces between oxide and nitride layers.
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
Achieves a 70%-88% reduction in interfacial charge density and a significant reduction in interfacial trap density, improving device performance with a dielectric constant of 10.6 and bandgap of 4.9 eV, while simplifying the fabrication process and reducing costs.
Implementation Method 1
employing a single process step in-situ metal-organic chemical vapor phase epitaxy using nitrogen as a carrier gas to provide for vertical metal-organic chemical vapor deposition wherein at least one ultra-wide-bandgap semiconductor is deposited via metal-organic chemical vapor deposition onto at least one high-electron-mobility transistor heterostructure
Data Source
AI summary
Described herein are methods, systems, and processes for in-situ oxide dielectric deposition in the same reactor, integrating III-Nitride and III-Oxide technology using N2 as carrier gas that results in a lower density of interface traps (charges).