Double-Layer Trench Gate Layout for End-Region Insulation Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor devices with a double-layered trench gate structure, the insulation withstand voltage of the intermediate insulation film at the end portion of the gate electrode layer is unreliable due to variations in manufacturing methods, leading to a decrease in insulation performance.
Innovation Solution
A semiconductor device design where the gate electrode layer at both ends of the trench gate structure is partially removed, and an embedded insulation film is inserted into the removal portion, creating an effective insulation distance larger than the thickness of the intermediate insulation film, ensuring consistent insulation withstand voltage regardless of manufacturing variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate electrode layer is fully retained at both ends of the trench gate structure, then the manufacturing process is simpler, but the insulation withstand voltage becomes unreliable due to manufacturing variations
Solution Approach 1:
The gate electrode layer is selectively removed (taken out) from the end portions of the trench gate structure where insulation reliability is compromised. This extraction eliminates the problematic regions that cause manufacturing variation sensitivity, while retaining the gate electrode layer in the central region where it provides necessary electrical functionality. The removal of the gate electrode layer at the ends prevents insulation breakdown without requiring complete structural removal.
Solution Approach 2:
Different regions of the trench gate structure are treated differently: the central region retains the gate electrode layer for electrical operation, while the end portions have the gate electrode layer removed to ensure insulation reliability. This local differentiation allows each region to have the appropriate structure for its specific function, resolving the contradiction between maintaining electrical performance and ensuring insulation withstand voltage.
2Reliability
If the gate electrode layer is partially removed at both ends and embedded insulation film is inserted, then the insulation performance becomes consistent, but the manufacturing process becomes more complex
Solution Approach 1:
The gate electrode layer is removed and the embedded insulation film is inserted into the end portions of the trench gate structure before final assembly steps. This preliminary action ensures that the insulation structure is established early, preventing subsequent manufacturing variations from affecting insulation reliability. By performing the removal and insertion operations in advance, the design achieves consistent insulation performance across production batches.
3Reliability
If the effective insulation distance is increased beyond the intermediate insulation film thickness, then the insulation withstand voltage is maintained, but the device structure becomes more complex
Solution Approach 1:
An embedded insulation film is introduced as an intermediary element between the intermediate insulation film and the external environment at the end portions of the trench gate structure. This embedded insulation film extends the effective insulation distance without requiring substantial structural changes to the core double-layered trench gate design. The intermediary insulation layer acts as a buffer that maintains insulation withstand voltage while minimizing overall structural complexity.
Data Source
AI summary
A semiconductor device includes a semiconductor switching element having a drift layer, a body region, a first impurity region, trench gate structures, a high impurity concentration layer, an interlayer insulation film, an upper electrode and a lower electrode. The body region is arranged on the drift layer. The first impurity region is arranged in a surface portion of the body region in the body region and has an impurity concentration higher than the drift layer. Each of the trench gate structures includes a trench. A shield electrode, an intermediate insulation film and a gate electrode layer are stacked through an insulation film in the trench. The high impurity concentration layer is arranged on a side opposite to the body region to sandwich the drift layer between the high impurity concentration layer and the body region. The interlayer insulation film is arranged on the trench gate structures.