SiC Schottky Electrode Formation via High-Temp Oxide Removal
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Solution Overview
Problem
Current methods for manufacturing semiconductor devices, such as Schottky barrier diodes, face challenges in achieving improved breakdown voltage characteristics due to uneven oxide film formation across different conductivity types, leading to surface roughness and inadequate contact between the substrate and the Schottky electrode.
Innovation Solution
A method involving the formation of an oxide film on a silicon carbide substrate at a temperature of 1250°C or more, followed by its removal to expose the surface, allowing for the formation of a Schottky electrode with reduced surface roughness and enhanced contact, and optionally using the remaining oxide film as an electric field relaxation Field Plate to improve breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an oxide film is formed by heating a substrate at a temperature below 1250°C, then the manufacturing process is simpler and energy consumption is lower, but the oxide film formation rate varies significantly between different conductivity types, causing exaggerated surface roughness and poor contact quality
Solution Approach 1:
The patent changes the heating temperature parameter from below 1250°C to 1250°C or higher. This parameter change makes the oxide film formation rate less dependent on conductivity type, thereby reducing surface roughness variation and improving contact quality between the Schottky electrode and substrate.
Solution Approach 2:
By heating at 1250°C or higher, the patent creates more uniform oxide film formation conditions across different conductivity type regions. This equalizes the oxide film formation rate across n-type and p-type regions, reducing the potential difference in surface roughness that would otherwise occur at lower temperatures.
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 results in improved breakdown voltage characteristics by reducing surface roughness and ensuring a satisfactory contact state between the substrate and the Schottky electrode, while the oxide film functions as an effective electric field relaxation mechanism.
Implementation Method 1
forming an oxide film on the main surface across the first conductivity type region and the second conductivity type region, by heating the substrate having the second conductivity type region formed therein at a temperature of 1250° C. or more
Data Source
AI summary
A method for manufacturing a semiconductor device includes the steps of preparing a substrate made of silicon carbide and having an n type region formed to include a main surface, forming a p type region in a region including the main surface, forming an oxide film on the main surface across the n type region and the p type region, by heating the substrate having the p type region formed therein at a temperature of 1250° C. or more, removing the oxide film to expose at least a part of the main surface, and forming a Schottky electrode in contact with the main surface that has been exposed by removing the oxide film.