Trench Gate Semiconductor Electrode Layout to Prevent Short-Circuits
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Solution Overview
Problem
The existing semiconductor device with a trench gate structure faces challenges in preventing short-circuits between the upper and lower electrodes while securing a sufficient bonding margin between the lower electrode and the contact via.
Innovation Solution
The semiconductor device incorporates a gate trench structure with a lower electrode and an upper electrode separated by an intermediate insulating film, along with a raised electrode that connects the lower electrode to the emitter electrode. The raised electrode includes a first raised electrode with a wider width and a second raised electrode with a narrower width, positioned between the first raised electrode and the gate trench, which helps in preventing short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the width of the raised electrode is increased to secure a bonding margin between the lower electrode and the contact via, then the bonding margin is improved, but the deposition state becomes worse and the upper electrode may be unintentionally left within the raised electrode causing a short-circuit
Solution Approach 1:
The raised electrode is divided into a first raised electrode with a first width and a second raised electrode with a second width narrower than the first width. This segmentation allows the first raised electrode to provide sufficient bonding margin while the second raised electrode maintains good deposition state, preventing short-circuits between the upper and lower electrodes.
Solution Approach 2:
Different portions of the raised electrode are given different widths according to their specific functional requirements. The first raised electrode has a wider width for bonding purposes, while the second raised electrode has a narrower width for deposition quality, creating local quality variations that resolve the contradiction.
2Reliability
If the width of the raised electrode is increased to secure a bonding margin, then the bonding margin is improved, but the risk of short-circuit between upper and lower electrodes increases
Solution Approach 1:
By segmenting the raised electrode into two portions with different widths, the invention secures adequate bonding margin in the first raised electrode while the second raised electrode with narrower width prevents deposition defects that could cause short-circuits, thus resolving the contradiction between bonding margin and short-circuit risk.
3Reliability
If the width of the raised electrode is increased, then the bonding margin is improved, but the embedding process becomes more difficult
Solution Approach 1:
The raised electrode is segmented into a first portion with wider width for bonding and a second portion with narrower width for easier embedding. This segmentation allows the manufacturing process to accommodate both requirements: sufficient bonding margin and ease of embedding material.
Solution Approach 2:
The embedding process is facilitated by having different width characteristics in different local regions of the raised electrode. The narrower second raised electrode portion is easier to embed material into, while the wider first raised electrode portion provides the necessary bonding margin.
Data Source
AI summary
A semiconductor device includes a semiconductor substrate, a gate insulating film formed on an inner wall of a groove that reaches a drift layer from a surface of the semiconductor substrate, a gate trench and a raised electrode that are formed inside the groove on the gate insulating film, an interlayer insulating film, and an emitter electrode. The raised electrode includes a first raised electrode and a second raised electrode, the first raised electrode being connected to the emitter electrode via a contact via that penetrates the interlayer insulating film, the second raised electrode being positioned between the first raised electrode and the gate trench in a direction in which the groove extends in plan view. The second raised electrode includes a narrow width portion having a width narrower than a width of the first raised electrode in plan view.