Planar-Trench Gate Semiconductor Structure for Lower Parasitic Capacitance
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Solution Overview
Problem
Semiconductor devices used in power control face challenges in reducing on-resistance and improving switching characteristics, particularly due to high parasitic capacitance and structural defects in control electrodes.
Innovation Solution
A semiconductor device design featuring a trench structure with a field plate electrode and a control electrode configuration that includes a planar and trench gate part, with a specific insulating film arrangement to reduce parasitic capacitance and enhance controllability, allowing for reduced on-resistance and improved switching characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trench gate structure is used to reduce parasitic capacitance, then switching characteristics are improved, but manufacturing complexity and structural defects increase
Solution Approach 1:
The control electrode is divided into two distinct parts: a planar gate part formed on the surface and a trench gate part formed within the trench structure. This segmentation allows each part to fulfill specific functions while reducing overall manufacturing complexity and structural defects compared to a complete trench gate structure.
Solution Approach 2:
Instead of forming a complete trench gate structure throughout, the invention uses a partial trench structure combined with a planar gate part. This partial action approach reduces parasitic capacitance between gate and drain while avoiding the manufacturing complexities and defects associated with full trench gate structures.
2Reliability
If on-resistance is reduced to improve power control, then device performance is enhanced, but parasitic capacitance increases
Solution Approach 1:
The control electrode is segmented into a planar gate part and a trench gate part. The trench gate part specifically reduces parasitic capacitance between gate and drain, while the planar gate part maintains low on-resistance by providing adequate gate control over the channel.
Solution Approach 2:
Different regions of the control electrode have different structures optimized for different functions: the trench gate part in the region where parasitic capacitance reduction is critical, and the planar gate part where low on-resistance is the priority. This local quality differentiation resolves the contradiction between on-resistance and parasitic capacitance.
Data Source
AI summary
A semiconductor device includes first, second and control electrodes, a semiconductor part and a conductive body. The semiconductor part is provided between the first and second electrodes. The semiconductor part includes a first layer of a first conductivity type, and a second layer of a second conductivity type. The second layer is provided between the first layer and the first electrode. The conductive body is provided in the semiconductor part, and faces the first layer via a first insulating film. The control electrode is provided between the second layer and the first electrode. The control electrode is apart from the conductive body. The control electrode includes first and second parts linked to each other. The first part faces the second layer via a second insulating film in a first direction. The second part faces the second layer along a second direction orthogonal to the first direction.