SiC Epitaxial Wafer Temperature Profiling for Carrier Uniformity
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Solution Overview
Problem
SiC epitaxial wafers exhibit low in-plane carrier concentration uniformity, particularly in the edge exclusion region, leading to variations in semiconductor device characteristics and reduced product yields.
Innovation Solution
Increasing the growth rate of the SiC epitaxial layer and adjusting the in-plane temperature distribution during film formation, with a temperature difference between inner and outer regions controlled to enhance carrier concentration uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional film formation methods are used, then manufacturing process is simple, but carrier concentration uniformity is poor (especially in edge exclusion region)
Solution Approach 1:
The patent applies local quality by creating a non-uniform temperature distribution across the substrate surface, with the center region maintained at a higher temperature than the peripheral region. This localized temperature control compensates for the edge exclusion effect, ensuring uniform carrier concentration across the entire epitaxial layer including the edge exclusion region.
Solution Approach 2:
The patent changes the temperature parameter distribution during film formation, specifically maintaining the center substrate temperature at 2200°C or higher while keeping the peripheral temperature lower. This parameter change in the temperature profile enables achieving carrier concentration uniformity of 3.8% or less, resolving the uniformity issue without overly complicating the process.
2Productivity
If growth rate is increased to improve productivity, then manufacturing efficiency improves, but carrier concentration uniformity deteriorates
Solution Approach 1:
The patent changes the temperature parameter during high-rate film formation, maintaining center substrate temperature at 2200°C or higher even when achieving growth rates of 61 μm/h or more. This parameter adjustment enables simultaneous achievement of high productivity and carrier concentration uniformity of 3.8% or less, breaking the traditional trade-off between growth rate and uniformity.
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
Achieves a carrier concentration uniformity of less than 3.8%, reducing variations in semiconductor device characteristics and allowing for reduced reliability testing, thereby lowering costs and improving product consistency.
Implementation Method 1
A SiC epitaxial wafer includes a SiC substrate and a SiC epitaxial layer laminated on the SiC substrate
Implementation Method 2
adjusting the in-plane temperature distribution of the SiC epitaxial layer
Data Source
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AI summary
A SiC epitaxial wafer according to the present embodiment includes: a SiC substrate; and a SiC epitaxial layer laminated on the SiC substrate, in which a carrier concentration uniformity of the SiC epitaxial layer is less than 3.8%, and the carrier concentration uniformity is a value obtained by dividing, by an average value, a difference between a maximum value and a minimum value of carrier concentrations of the SiC epitaxial layer measured along a straight line passing through a center of the SiC epitaxial layer when seen in a plan view.