SiC Schottky Diode Interface Structure for Lower Forward Voltage
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Solution Overview
Problem
Silicon carbide (SiC) Schottky barrier diodes (SBDs) face challenges in reducing forward voltage (VF) to achieve low-loss performance, as existing designs lack effective methods to minimize the Schottky barrier and optimize the structure for improved efficiency and manufacturing yield.
Innovation Solution
The semiconductor device incorporates a silicon carbide layer with a titanium nitride layer and an intermediate silicon nitride layer, which reduces the Schottky barrier by making the titanium nitride layer polycrystalline with oblique crystal axes, and includes a method for manufacturing that involves a heat treatment in a nitrogen atmosphere to form the intermediate layer, optimizing thickness and nitrogen concentration for reduced forward voltage and increased on-current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a silicon carbide Schottky barrier diode is designed with conventional structures, then the device can operate at high temperature and high breakdown voltage, but the forward voltage remains high resulting in energy loss
Solution Approach 1:
An intermediate layer containing silicon nitride is introduced between the titanium nitride layer and the n-type silicon carbide region. This intermediate layer acts as a mediator that reduces the Schottky barrier height at the interface, thereby lowering the forward voltage and reducing energy loss while maintaining device reliability
Solution Approach 2:
The titanium nitride layer is designed with polycrystalline structure and oblique crystal axes orientation, and the intermediate layer has controlled thickness and nitrogen concentration. These parameter changes optimize the interface properties to reduce the Schottky barrier while maintaining stable operation
2Loss of energy
If the titanium nitride layer is made single-crystalline with aligned crystal axes, then the Schottky barrier is stable, but the forward voltage cannot be reduced effectively
Solution Approach 1:
The titanium nitride layer is designed with polycrystalline structure and oblique crystal axes orientation instead of single-crystalline structure with aligned axes. This parameter change in crystal structure allows effective reduction of Schottky barrier and forward voltage while managing the complexity through controlled deposition parameters
3Loss of energy
If an intermediate layer is added between the titanium nitride layer and silicon carbide region, then the Schottky barrier is reduced and forward voltage decreases, but the device structure becomes more complex
Solution Approach 1:
An intermediate layer containing silicon nitride is introduced between the titanium nitride layer and the n-type silicon carbide region. This intermediate layer acts as a mediator that reduces the Schottky barrier height at the interface, thereby lowering the forward voltage and reducing energy loss while maintaining device reliability
Solution Approach 2:
The intermediate layer has optimized thickness and nitrogen concentration parameters that enable effective Schottky barrier reduction. By controlling these parameters, the layer achieves the desired electrical performance without excessive 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
The solution effectively reduces the forward voltage in SiC SBDs, enhancing their low-loss performance, improving manufacturing yield, and reducing manufacturing costs by stabilizing the forward voltage and minimizing reverse leakage current.
Implementation Method 1
an intermediate layer provided between the titanium nitride layer and the first silicon carbide region and containing silicon nitride
Implementation Method 2
a heat treatment in a nitrogen atmosphere to form the intermediate layer
Data Source
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AI summary
A semiconductor device according to an embodiment includes a first electrode, a second electrode, a silicon carbide layer provided between the first electrode and the second electrode and including a first silicon carbide region of n type, a titanium nitride layer provided between the first electrode and the first silicon carbide region, and an intermediate layer provided between the titanium nitride layer and the first silicon carbide region and containing silicon nitride.