SiC Semiconductor Contact Resistance Stabilization
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Solution Overview
Problem
In semiconductor devices using silicon carbide, variations in contact resistance between the contact electrode and the n-type region lead to inconsistent device characteristics, particularly due to variations in the Schottky barrier height, which affects the on-resistance of transistors and overall device performance.
Innovation Solution
Incorporating an oxygen region with oxygen atoms bonded to four carbon atoms in the silicon carbide layer between the contact electrode and the n-type region, which reduces the Schottky barrier height and stabilizes it, thereby minimizing variations in contact resistance and achieving ohmic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a contact electrode is formed directly on the n-type silicon carbide region, then the device structure is simple, but the contact resistance varies due to Schottky barrier height variations
Solution Approach 1:
An oxygen region is introduced as an intermediary layer between the contact electrode and the n-type silicon carbide region. This oxygen region acts as a mediator that reduces and stabilizes the Schottky barrier height, ensuring consistent contact resistance while maintaining structural simplicity. The oxygen region is formed by implanting oxygen ions into the silicon carbide layer at a specific depth range (1 μm to 5 μm from the surface) and performing heat treatment to activate the oxygen atoms.
2Reliability
If the Schottky barrier height is reduced without oxygen region, then contact resistance decreases, but the barrier height becomes unstable and varies
Solution Approach 1:
The physical and chemical parameters of the silicon carbide layer are modified by introducing oxygen atoms at controlled concentrations and depths. The oxygen concentration in the oxygen region is maintained between 1×10^19 atoms/cm³ to 1×10^21 atoms/cm³, and the depth is controlled at 1 μm to 5 μm from the surface. These parameter changes create a stable oxygen region that consistently reduces the Schottky barrier height while maintaining stability across different devices and operating conditions.
3Reliability
If oxygen atoms are introduced into the silicon carbide layer, then the Schottky barrier height is stabilized, but the manufacturing process becomes more complex
Solution Approach 1:
The oxygen region is formed in advance during the semiconductor device manufacturing process, before the contact electrode is formed. Oxygen ions are implanted into the silicon carbide layer at the desired depth and concentration, followed by heat treatment to activate the oxygen atoms. This preliminary action ensures that the oxygen region is already in place and optimized before electrode formation, simplifying the overall manufacturing process by integrating the oxygen introduction step into the existing fabrication sequence.
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 inclusion of an oxygen region with oxygen atoms bonded to four carbon atoms in the silicon carbide layer reduces contact resistance, stabilizes the Schottky barrier height, and enhances the reliability and performance of semiconductor devices by ensuring consistent device characteristics regardless of the contact electrode material.
Implementation Method 1
Incorporating an oxygen region with oxygen atoms bonded to four carbon atoms in the silicon carbide layer between the contact electrode and the n-type region, which reduces the Schottky barrier height and stabilizes it, thereby minimizing variations in contact resistance
Implementation Method 2
Incorporating an oxygen region with oxygen atoms bonded to four carbon atoms in the silicon carbide layer between the contact electrode and the n-type region, which reduces the Schottky barrier height and stabilizes it
Data Source
AI summary
A semiconductor device of an embodiment includes an electrode; and a silicon carbide layer in contact with the electrode and including: a first silicon carbide region of n-type; and a second silicon carbide region disposed between the first silicon carbide region and the electrode, in contact with the electrode, and containing at least one oxygen atom bonded to four carbon atoms.