SiC Substrate Surface Orientation Control for High Channel Mobility
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Solution Overview
Problem
Conventional methods for manufacturing semiconductor devices fail to effectively employ the (0-33-8) plane orientation for high channel mobility, leading to insufficient microscopic control of the channel surface, which limits the performance of semiconductor devices.
Innovation Solution
A semiconductor device with a substrate having a surface constructed by alternately providing planes with (0-33-8) and (0-11-1) orientations, along with a gate insulating film and gate electrode, where the surface is chemically treated through thermal etching in a halogen atmosphere to enhance channel mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a normal silicon carbide substrate obtained by cutting an ingot along a plane orientation of (0-33-8) is used, then the surface corresponds to the (0-33-8) plane macroscopically, but the plane orientation of (0-33-8) is present at an unexpectedly low ratio microscopically, resulting in insufficient channel mobility
Solution Approach 1:
The invention changes the macroscopic plane orientation parameter from (0-33-8) to (0-00-1), while using chemical etching to transform the microscopic surface structure to predominantly expose (0-33-8) planes. This parameter transformation resolves the contradiction by achieving high (0-33-8) plane ratio through chemical processing rather than relying on mechanical cutting precision.
Solution Approach 2:
The invention replaces the mechanical cutting method with chemical etching method to control the microscopic plane orientation. Instead of relying on mechanical precision to cut the substrate at (0-33-8) orientation, the process uses chemical etching to selectively remove material and expose (0-33-8) planes on a (0-00-1) macroscopic surface, thereby achieving the desired microscopic structure through chemical rather than mechanical means.
2Reliability
If chemical etching is performed to increase the ratio of (0-33-8) planes, then channel mobility is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The invention performs preliminary chemical etching treatment on the (0-00-1) macroscopic surface before subsequent device fabrication steps. This preliminary action creates the optimal microscopic surface structure with high (0-33-8) plane ratio, ensuring high channel mobility from the outset and preventing the need for additional corrective processing steps later in the manufacturing process.
Solution Approach 2:
The invention changes the surface chemical composition and crystallographic exposure through controlled chemical etching. By adjusting etching parameters such as temperature, time, and chemical solution composition, the process selectively exposes (0-33-8) planes while maintaining the (0-00-1) macroscopic orientation, thereby improving channel mobility through controlled chemical transformation rather than mechanical processing.
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 increases channel mobility by microscopically controlling the channel surface, leading to improved performance of semiconductor devices.
Implementation Method 1
the surface is chemically treated through thermal etching in a halogen atmosphere to enhance channel mobility
Data Source
AI summary
A substrate has a surface made of a semiconductor having a hexagonal single-crystal structure of polytype 4H. The surface of the substrate is constructed by alternately providing a first plane having a plane orientation of (0-33-8), and a second plane connected to the first plane and having a plane orientation different from the plane orientation of the first plane. A gate insulating film is provided on the surface of the substrate. A gate electrode is provided on the gate insulating film.