SiC Gate Pad Structure for Insulating Film Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional silicon carbide semiconductor devices experience damage to the insulating film between the p-type semiconductor region and the wiring layer during switching operations due to the configuration of the gate pad and wiring layer.
Innovation Solution
A silicon carbide semiconductor device configuration featuring a p-type semiconductor region with a two-layer structure, including a 4H-SiC lower layer and a 3C-SiC upper layer under the gate pad, which separates the displacement current path from the gate and field insulating films, reducing the electric field applied to these films and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wiring layer is provided on the top surface of a p-type semiconductor region with an insulating film interposed, then electrical connection is achieved, but the insulating film may be damaged during switching operation
Solution Approach 1:
A gate protection region of second conductivity type is introduced as an intermediary layer between the p-type semiconductor region and the gate pad. This intermediary region redirects the displacement current path away from the insulating film, preventing direct electric field damage while maintaining necessary electrical connections.
Solution Approach 2:
The solution adds a vertical dimension to the current path management by creating a multi-layer structure with the gate protection region extending from the p-type semiconductor region through the insulating film to the gate pad, thereby providing an alternative current pathway in the depth direction that bypasses the vulnerable insulating film area.
2Ease of operation
If displacement current flows through the insulating film during switching operation, then gate control is achieved, but the insulating film suffers damage
Solution Approach 1:
The gate protection region serves as a mediator that allows displacement current to flow for gate control while preventing direct current flow through the insulating film. The gate protection region captures and redirects the displacement current, maintaining gate functionality while protecting the insulating film from damage.
Solution Approach 2:
The gate structure is segmented into distinct regions: the gate protection region separate from the main gate pad. This segmentation allows the displacement current to be handled by the dedicated gate protection region while the main gate pad maintains control functionality, effectively separating the harmful current path from the functional gate control path.
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 configuration effectively avoids damage to the insulating films during switching operations, enhancing the reliability of the silicon carbide semiconductor device by redirecting the displacement current away from the gate and field insulating films.
Implementation Method 1
separates the displacement current path from the gate and field insulating films, reducing the electric field applied to these films
Data Source
AI summary
A silicon carbide semiconductor device includes: a drift layer of a first conductivity-type; a semiconductor region of a second conductivity-type provided on a top surface side of the drift layer in an intermediate part between an active part and an edge termination part; a first insulating film provided on a top surface of the semiconductor region; a wiring layer provided on a top surface of the first insulating film; a second insulating film provided on a top surface of the wiring layer; and a gate pad provided on a top surface of the second insulating film so as to be electrically connected to the wiring layer, wherein the semiconductor region includes a first region having a 4H structure overlapping with at least a part of the wiring layer in a depth direction, and a second region having a 3C structure provided on a top surface side of the first region.