Trench Gate and Field Electrode Layout for Low-Resistance MOSFETs
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Solution Overview
Problem
The existing design of power transistor components, such as power MOSFETs, requires multiple gate fingers and corresponding source electrode sections, which reduces the active component area and prevents the formation of active regions under gate fingers, leading to increased resistance and reduced efficiency.
Innovation Solution
The transistor component features gate electrodes and field electrodes arranged in common trenches, with field electrodes having contact sections that connect to the source metallization, allowing for electrical connection of gate electrode sections across trenches, eliminating the need for gate fingers and preserving active regions under the source metallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple gate fingers are provided to connect gate electrodes to the gate node, then the gate electrodes can be electrically connected, but the active component area is reduced and active regions cannot be formed under the gate fingers
Solution Approach 1:
The patent transitions from a planar gate finger structure to a vertical three-dimensional structure by arranging gate electrodes and field electrodes in common trenches. This vertical arrangement eliminates the need for horizontal gate fingers, allowing active regions to be formed continuously under the source metallization while maintaining electrical connection of gate electrodes through the trench structure.
Solution Approach 2:
The patent implements nesting by placing field electrodes inside the gate electrodes within the same trenches. This nested configuration allows both gate and field electrodes to coexist in the same vertical space, eliminating the need for separate gate finger structures and maximizing the active component area.
2Reliability
If gate fingers are provided to connect gate electrodes, then electrical connection is achieved, but resistance increases due to the additional structural complexity
Solution Approach 1:
The patent merges the functions of gate electrode connection and field electrode structure into a unified trench-based architecture. By combining these elements vertically in common trenches with shared insulation layers, the design eliminates the need for separate gate finger structures and complex source electrode sections, thereby reducing overall device complexity while maintaining electrical connectivity.
3Reliability
If field electrodes comprise multiple terminal regions for low resistance connection, then connection resistance is reduced, but gate electrodes are subdivided into multiple sections requiring additional gate fingers
Solution Approach 1:
The patent resolves the subdivision problem by transitioning to a vertical three-dimensional structure where field electrodes with multiple terminal regions can be arranged within common trenches without requiring horizontal gate fingers. This vertical arrangement allows continuous active regions to form under the source metallization while maintaining low connection resistance through the multi-terminal field electrode structure.
Data Source
AI summary
A transistor includes: gate electrodes and field electrodes, wherein in each case one gate electrode and one field electrode are arranged one above another in a vertical direction in a common trench of a semiconductor body; a gate pad to which the gate electrodes are connected; and a source metallization arranged above the semiconductor body. The field electrodes of a first group include at least one contact section. The at least one contact section is arranged between two sections of a gate electrode arranged in the same trench and is connected to the source metallization. The two sections of the gate electrode are separated from one another in a region of the contact section. At least one of the two sections of the gate electrode arranged in the same trench is electrically connected to a gate electrode arranged in a further trench by way of a gate connecting electrode.