HEMT Ohmic Contact Interface With Silicon-Oxygen Intermediary
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Solution Overview
Problem
High-electron-mobility transistors face performance degradation due to elevated ohmic contact resistance, which can lead to yield loss if the resistance falls outside acceptable criteria.
Innovation Solution
A structure and method for forming an ohmic contact in high-electron-mobility transistors, involving a layer stack with a metal layer positioned between a region comprising oxygen atoms and a semiconductor layer, reducing ohmic contact resistance by modifying the interface with a silicon and oxygen layer stack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional ohmic contact structure is used, then the device structure is simple, but the ohmic contact resistance is elevated which degrades device performance
Solution Approach 1:
A silicon-oxygen layer is introduced as an intermediary between the metal contact and the GaN semiconductor layer. This intermediate layer modifies the interface properties to achieve lower contact resistance without directly contacting the semiconductor, thereby improving reliability while adding only moderate structural complexity.
Solution Approach 2:
The interface properties are modified by changing the chemical composition (adding silicon and oxygen) at the contact interface. This parameter change in the interfacial layer composition enables reduced ohmic contact resistance and improved device performance.
2Reliability
If the ohmic contact resistance is reduced by modifying the interface, then device performance improves, but the manufacturing process becomes more complex
Solution Approach 1:
The silicon-oxygen layer is formed in advance before the metal contact is deposited. This preliminary preparation of the interface layer simplifies the overall manufacturing process by separating the interface modification step from the metal deposition step, making the process more controllable and easier to manufacture.
3Reliability
If a metal layer is positioned between the oxygen region and semiconductor layer, then ohmic contact resistance is reduced, but the contact structure becomes more complex
Solution Approach 1:
The contact structure uses a composite approach with a silicon-oxygen layer combined with a metal layer. This composite structure leverages the beneficial properties of both materials: the silicon-oxygen layer provides interface modification for low resistance, while the metal layer provides good conductivity and mechanical properties, achieving reduced ohmic contact resistance with manageable complexity.
Data Source
AI summary
Structures including an ohmic contact for a high-electron-mobility transistor and methods of forming such structures. The structure comprises a layer stack on a substrate and a device structure including an ohmic contact. The layer stack includes a plurality of semiconductor layers each comprising a compound semiconductor material. The ohmic contact includes a metal layer in a contacting relationship with a portion of at least one of the semiconductor layers of the layer stack and a region comprising oxygen atoms, and the metal layer is positioned between the region and the portion of the at least one of the semiconductor layers of the layer stack.