Silicon Carbide Base Body Dislocation Management via Surface Tilt
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in manufacturing high-quality silicon carbide base bodies for semiconductor devices lies in the presence of basal plane dislocations, which lead to stacking faults and degradation of forward-direction characteristics, particularly under high current conditions.
Innovation Solution
A method involving the preparation of a silicon carbide base body with a tilted surface, followed by the formation and partial removal of layers to reduce basal plane dislocations by converting them into threading edge dislocations, thereby suppressing the expansion of stacking faults and enhancing the quality of the silicon carbide base body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicon carbide base body is manufactured using conventional methods, then production is simpler and faster, but basal plane dislocations remain dense leading to stacking faults and degraded forward-direction characteristics
Solution Approach 1:
The manufacturing process is divided into distinct stages: forming a tilted surface on the silicon carbide base body, growing an epitaxial layer on the tilted surface, and selectively removing portions of the epitaxial layer. This segmentation allows each stage to address specific dislocation issues independently, improving reliability without overwhelming complexity
Solution Approach 2:
A tilted surface is formed on the silicon carbide base body before epitaxial layer growth. This preliminary action creates a surface geometry that promotes the conversion of basal plane dislocations to threading edge dislocations during the subsequent epitaxial growth process, preventing stacking faults before they occur
2Ease of manufacture
If basal plane dislocations are present in the silicon carbide base body, then manufacturing is easier, but stacking faults expand and forward-direction characteristics degrade under high current conditions
Solution Approach 1:
The surface tilt angle is controlled within a specific range (0° to 15° relative to the (0001) plane) to optimize the conversion of basal plane dislocations to threading edge dislocations. This parameter change maintains ease of manufacture while significantly improving stacking fault stability under high current conditions
Solution Approach 2:
The epitaxial layer growth process, which would normally propagate basal plane dislocations and cause stacking faults, is instead used to convert these harmful dislocations into beneficial threading edge dislocations through the tilted surface geometry, eliminating the harm while maintaining manufacturing simplicity
3Productivity
If the density of basal plane dislocations is high, then material production is more efficient, but the quality and stability of the silicon carbide base body deteriorates
Solution Approach 1:
Instead of controlling dislocation density through bulk material growth parameters alone, the invention introduces a surface dimension factor by creating a tilted surface. This dimensional change allows dislocation management to occur at the surface interface during epitaxial growth, improving quality without sacrificing production efficiency
Solution Approach 2:
The conventional approach of controlling dislocation density through mechanical growth parameters is replaced with a geometric approach using surface tilt. This substitution simplifies the control mechanism while achieving better dislocation density management and overall base body quality
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 effectively reduces the density of basal plane dislocations, leading to improved stability and characteristics of the silicon carbide base body and semiconductor devices, including suppressed expansion of stacking faults and stable forward-direction characteristics.
Implementation Method 1
forming a first layer at the first base body surface... A first-layer surface of the first layer is exposed by the removing of the portion. The first-layer surface is tilted with respect to a (0001) plane of the first layer
Data Source
AI summary
According to one embodiment, a method for manufacturing a silicon carbide base body is disclosed. The method can include preparing a first base body including silicon carbide. The first base body includes a first base body surface tilted with respect to a (0001) plane of the first base body. A first line segment where the first base body surface and the (0001) plane of the first base body intersect is along a [11-20] direction of the first base body. The method can include forming a first layer at the first base body surface. The first layer includes silicon carbide. The method can include removing a portion of the first layer. The first-layer surface is tilted with respect to a (0001) plane of the first layer. A second line segment where the first-layer surface and the (0001) plane of the first layer intersect is along a [−1100] direction.