SiC Ohmic Electrode Wire Adhesion via Silicon Interlayer
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Solution Overview
Problem
In silicon carbide semiconductor devices, the deposition of carbon between the electrode and wire leads to poor adhesion and formation of Schottky contacts, affecting the durability and electric characteristics.
Innovation Solution
A method involving the formation of a SiC layer, a first metal layer with no carbon atoms, and a Si layer, followed by thermal treatment to prevent direct contact between Si and SiC, thereby avoiding Schottky contact and enhancing wire adhesion by forming a silicide layer with no carbon on the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal treatment is performed to form an ohmic electrode by reacting metal with SiC substrate, then ohmic contact is achieved, but carbon is deposited on the electrode surface causing poor wire adhesion
Solution Approach 1:
A silicon layer is introduced as an intermediary between the metal electrode and the SiC substrate. During thermal treatment, the metal reacts with the silicon layer to form a silicide layer, preventing direct contact between metal and SiC, thereby avoiding carbon deposition while maintaining ohmic contact properties
Solution Approach 2:
The electrode structure is segmented into multiple layers: metal layer, silicide layer (formed during thermal treatment), and silicon layer. This segmentation allows the reaction to occur at the metal-silicon interface rather than metal-SiC interface, preventing carbon contamination of the electrode surface
2Ease of manufacture
If a simple metal layer is formed on SiC substrate, then manufacturing process is simple, but Schottky contact forms due to direct Si-SiC contact
Solution Approach 1:
The silicon layer serves as a mediator that enables ohmic contact formation without complicating the manufacturing process significantly. The silicon layer is deposited using standard semiconductor fabrication techniques, and the subsequent thermal treatment forms the silicide layer in situ, maintaining process simplicity while ensuring reliable ohmic contact
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 method improves the adhesion of the wire to the ohmic electrode by preventing carbon deposition and ensuring a good ohmic contact, thereby enhancing the durability and electric characteristics of the silicon carbide semiconductor device.
Implementation Method 1
thermal treatment to form the silicide layer
Implementation Method 2
forming a silicide layer with no carbon on the surface
Implementation Method 3
thermal treatment to form the silicide layer
Data Source
AI summary
The present invention provides a silicon carbide semiconductor device having an ohmic electrode improved in adhesion of a wire thereto by preventing deposition of carbon so as not to form a Schottky contact, as well as a method for manufacturing such a silicon carbide semiconductor device. In the SiC semiconductor device, upon forming the ohmic electrode, a first metal layer made of one first metallic element is formed on one main surface of a SiC layer. Further, a Si layer made of Si is formed on an opposite surface of the first metal layer to its surface facing the SiC layer. The stacked structure thus formed is subjected to thermal treatment. In this way, there can be obtained a silicon carbide semiconductor device having an ohmic electrode adhered well to a wire by preventing deposition of carbon atoms on the surface layer of the electrode and formation of a Schottky contact resulting from Si and SiC.