Super Junction Pillar Layout to Reduce SiC Epitaxial Voids
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Solution Overview
Problem
The formation of voids in the manufacturing process of silicon carbide semiconductor devices with super junction structures leads to increased leakage current and invalid regions, resulting in higher costs due to the need for additional processes to reduce leakage current.
Innovation Solution
A semiconductor device design featuring alternating n-type and p-type pillars with a surrounding pillar part of a specific impurity concentration and width configuration, which minimizes the formation of voids during epitaxial growth, thereby reducing invalid regions and leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If embedding epitaxial method is used to form SJ structure, then high withstand voltage and low resistance are achieved, but voids are formed in trench end portions causing increased leakage current
Solution Approach 1:
The patent changes the geometric parameters of the pillar structure by setting the pillar width to 0.5 μm or less and controlling the product of impurity concentration and width (N·W) to be 1×10^13 to 1×10^16 cm^-2. This parameter optimization prevents void formation during epitaxial growth while maintaining the super junction structure's electrical performance, thereby reducing leakage current without additional processing steps.
2Reliability
If additional processes are implemented to reduce leakage current, then reliability improves, but manufacturing cost increases
Solution Approach 1:
The patent achieves self-service by designing the pillar structure parameters (width ≤0.5 μm and N·W product control) such that the epitaxial growth process automatically prevents void formation. The structure itself provides the solution to leakage current without requiring external additional processes like trench formation or channel stopper regions, thereby maintaining low manufacturing cost while improving reliability.
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 proposed design effectively reduces void formation and leakage current, minimizing the need for additional processing and lowering manufacturing costs while maintaining high withstand voltage and low resistance.
Implementation Method 1
an epitaxial method has an advantage in consideration of productivity
Data Source
AI summary
The present disclosure relates a semiconductor device using a super junction structure, and includes: a semiconductor base body of a first conductivity type; a pillar part including a plurality of first pillars of a first conductivity type and a plurality of second pillars of a second conductivity type provided on the semiconductor base body to protrude in a thickness direction of the semiconductor base body; a pillar surrounding part of a first conductivity type or a second conductivity type provided around the pillar part; and a semiconductor element in which the pillar part is provided as an active region, wherein the plurality of first and second pillars have a striped shape in a plan view, and are alternately arranged in parallel to each other in a pillar width direction perpendicular to a longitudinal direction of each of the pillars.