Trench Semiconductor Source Electrode Layout for Lower Turn-On Loss
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Solution Overview
Problem
Semiconductor trench devices face challenges in improving switching characteristics due to parasitic capacitances, which result in undesired turn-on losses during switching between on- and off-states.
Innovation Solution
The semiconductor device incorporates a plurality of trenches with a gate electrode, a source electrode subdivided into parts with varying conductance per unit length, and an auxiliary electrode, along with resistive coupling between the source electrode and the source contact area, to reduce parasitic capacitances and turn-on losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional trench structure with source electrode is used, then the device structure is simple, but parasitic capacitances cause turn-on losses and poor switching characteristics
Solution Approach 1:
The source electrode is divided into multiple segments (first source electrode portion, second source electrode portion, third source electrode portion) with different conductances. This segmentation allows each portion to contribute differently to the electrical characteristics, reducing parasitic capacitance effects while maintaining structural organization and avoiding complete redesign of the trench system.
Solution Approach 2:
Different portions of the source electrode are assigned different conductance values (first portion has higher conductance, second portion has lower conductance). This local differentiation optimizes the electrical performance by reducing turn-on losses in specific regions while maintaining overall device functionality, without requiring complete structural complexity.
2Reliability
If the source electrode has uniform conductance, then the manufacturing is simple, but turn-on voltage tails occur due to parasitic capacitances
Solution Approach 1:
The source electrode is designed with spatially varying conductance properties - the first portion has higher conductance while the second portion has lower conductance. This local quality differentiation suppresses turn-on voltage tails and improves switching characteristics without requiring completely complex fabrication processes.
Solution Approach 2:
The conductance parameter of the source electrode is varied across different portions rather than maintaining uniform conductance. By changing this electrical parameter locally, the device achieves better switching characteristics and reduced parasitic capacitance effects while keeping the overall structure manufacturable.
3Loss of energy
If the source electrode is directly connected to the source contact area, then the electrical connection is simple, but the shielding effect of trenches causes poor switching behavior
Solution Approach 1:
The electrical connection between source electrode and source contact area is segmented into multiple portions with different conductances. This segmentation reduces the shielding effect of trenches and minimizes turn-on losses while maintaining a structured but not overly complex connection architecture.
Solution Approach 2:
The source electrode portions act as intermediaries between the source contact area and the active device regions. By using multiple portions with different conductances, the system mediates the electrical connection to reduce parasitic capacitance effects and improve switching behavior without direct simple connection.
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 suppresses turn-on voltage tails, reducing turn-on losses and enhancing switching characteristics by introducing a resistive coupling that mitigates the shielding effect of the trenches.
Implementation Method 1
The source wiring line and the auxiliary electrode are electrically connected in series between the source contact area and the source electrode
Implementation Method 2
parasitic capacitances have an impact on the overall switching behavior of the device
Data Source
AI summary
A semiconductor device is proposed. The semiconductor device includes trenches extending into a semiconductor body from a first main surface. A first group of the trenches includes a gate electrode. A second group of the trenches includes a source electrode, the source electrode being subdivided into at least a first part and a second part. A conductance per unit length of the first part along a longitudinal direction of the source electrode is smaller than a conductance per unit length of the second part along the longitudinal direction of the source electrode, the second part being electrically coupled to a source contact area via the first part. A mesa region bounded by a trench of the first group and a trench of the second group includes a source region electrically connected to the source contact area.