Trench Gate Semiconductor Structure for Smooth Metal Film Coverage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor devices with trenches, the large step between the semiconductor substrate and interlayer insulating film surfaces can lead to deteriorated metal film coverage and step cuts, compromising the reliability of the metal film.
Innovation Solution
The semiconductor device design includes a connection surface on the semiconductor substrate that connects the upper surface to the trench side surface, with the gate and interlayer insulating films' surfaces positioned below, allowing the metal film to cover these areas smoothly, and an etching process that forms inclined surfaces to reduce level differences and enhance coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the interlayer insulating film is positioned below the semiconductor substrate surface to reduce device height, then the device integration density is improved, but the large step between surfaces causes deteriorated metal film coverage and step cuts
Solution Approach 1:
The patent applies curvature by forming an inclined connection surface instead of a sharp step between the semiconductor substrate upper surface and the interlayer insulating film upper surface. This curved transition surface reduces the step difference, enabling the metal film to form a continuous, uniform layer without step cuts or coverage deterioration, while still maintaining the reduced device height objective.
2Reliability
If the gate insulating film and interlayer insulating film are positioned below the connection surface to improve metal film coverage, then the metal film covering property is improved, but the electric field concentration and gate leakage current increase
Solution Approach 1:
The inclined connection surface creates a gradual transition rather than a sharp corner, distributing the electric field more evenly and avoiding concentration at abrupt interfaces. This curved geometry reduces gate leakage current while still allowing the metal film to cover the area uniformly.
Data Source
AI summary
A semiconductor device includes a semiconductor substrate having a trench adjacent to an upper surface, a gate insulating film inside the trench, a gate electrode on the gate insulating film inside the trench, and an interlayer insulating film covering the gate electrode inside the trench. The semiconductor substrate has a connection surface that connects between the upper surface of the semiconductor substrate and a side surface of the trench and is located below the upper surface of the semiconductor substrate. An upper surface of the gate insulating film is located below the connection surface. An upper surface of the interlayer insulating film is located below the upper surface of the gate insulating film. A metal film is disposed to cover the upper surface of the semiconductor substrate, the connection surface, the upper surface of the gate insulating film, and the upper surface of the interlayer insulating film.