SiC Schottky Diode Oxygen Interface for Stable Barrier Height
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Solution Overview
Problem
In silicon carbide Schottky barrier diodes, variations in the height of the Schottky barrier between the silicon carbide layer and the electrode lead to fluctuations in rectification characteristics, potentially causing issues with forward bias voltage, excessive forward current, and reduced breakdown voltage.
Innovation Solution
Incorporating an oxygen region within the silicon carbide layer where one oxygen atom bonds with four silicon atoms, stabilizing the Schottky barrier height at approximately 0.8 eV through Fermi-level pinning, thereby suppressing variations in the barrier height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the Schottky barrier height is reduced to enable low forward bias voltage, then forward voltage loss is improved, but the breakdown voltage decreases and reliability deteriorates
Solution Approach 1:
The patent introduces an oxygen region specifically at the anode electrode contact interface with a concentration of 1×10^18 to 1×10^21 atoms/cm³, while keeping other regions free of oxygen. This localized modification creates different electrical properties at the contact interface versus the bulk material, enabling low forward voltage drop at the interface while maintaining high breakdown voltage in the drift region.
Solution Approach 2:
The patent changes the oxygen concentration parameter in the silicon carbide layer to control Schottky barrier height. By introducing oxygen at specific concentrations (1×10^18 to 1×10^21 atoms/cm³) in the contact region, the Schottky barrier height is reduced to 0.7-0.9 eV, optimizing the trade-off between forward voltage loss and breakdown voltage.
2Adaptability or versatility
If the Schottky barrier height varies, then manufacturing flexibility is improved, but rectification characteristics stability deteriorates
Solution Approach 1:
The patent performs preliminary oxygen introduction into the silicon carbide layer before forming the anode electrode. This preliminary action of creating the oxygen region in advance ensures that when the electrode is formed, the Schottky barrier height is already stabilized at the desired level, preventing variations and ensuring consistent rectification characteristics across different material selections.
Solution Approach 2:
The oxygen region acts as an intermediary layer between the anode electrode and the n-type silicon carbide drift region. This intermediary oxygen-containing region mediates the electrical interaction, stabilizing the Schottky barrier height at 0.7-0.9 eV regardless of the specific electrode material used, thereby enabling material selection flexibility while maintaining rectification stability.
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 ensures stable rectification characteristics and allows for the selection of arbitrary materials for the anode electrode, enhancing the semiconductor device's reliability and manufacturing flexibility.
Implementation Method 1
stabilizing the Schottky barrier height at approximately 0.8 eV through Fermi-level pinning
Data Source
AI summary
According to an embodiment, provided is a semiconductor device including: a first electrode; a second electrode; and a silicon carbide layer disposed between the first electrode and the second electrode, the silicon carbide layer including: a first silicon carbide region of an n-type; and a second silicon carbide region disposed between the first silicon carbide region and the first electrode, the second silicon carbide being in contact with the first electrode, and the second silicon carbide containing one oxygen atom bonding with four silicon atoms.