Vertical Trench Transistor Layout for Fast Drain Transient Sensing

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Solution Overview

Problem

Vertical transistor devices face challenges in sensing fast transients in drain to source voltage variations, which can lead to dynamic avalanches and return-on events, causing potential failure or degradation, and existing solutions require separate sense electrodes that increase area and complexity.

Innovation Solution

Incorporating a sense electrode contact at a lateral position spaced apart from the control electrode contact within the same trench electrode, allowing the trench electrode to be used capacitively for sensing backside potential variations, thereby reducing area requirements and enabling internal or external countermeasures for fast transient detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate sense electrode is added beside the transistor device for sensing backside potential, then sensing capability is improved, but device area increases

Engineering Contradiction:
Improvesensing capabilityVSAvoiddevice area
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The trench electrode is designed to serve dual functions: as a control electrode for applying electrical potential to the semiconductor body and as a sense electrode for sensing backside potential variations through capacitive coupling. This multi-functionality eliminates the need for a separate sense electrode, thereby maintaining sensing capability while reducing device area.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the control electrode and sense electrode functions into a single trench electrode structure. By providing both a control electrode contact and a sense electrode contact connected to the same trench electrode, the design combines what would traditionally be separate components, reducing overall device area while maintaining both control and sensing capabilities.

Inventive Principle:
Principle #5Merging (Combining)

2Area of stationary object

If the sense electrode contact is placed close to the control electrode contact, then area is reduced, but sensing accuracy deteriorates due to internal resistance

Engineering Contradiction:
Improvedevice areaVSAvoidsensing accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The trench electrode is designed with spatially differentiated contact positions: the control electrode contact is positioned at a first lateral position optimized for control signal application, while the sense electrode contact is positioned at a second lateral position spaced apart to minimize the influence of internal resistance on sensing accuracy. This local differentiation of contact functions along the trench electrode resolves the contradiction between area reduction and sensing accuracy.

Inventive Principle:
Principle #3Local quality

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 allows for effective sensing of fast transients and potential failures, enabling timely countermeasures while maintaining a compact design by utilizing the active trench electrode for both control and sensing functions, thus preventing device degradation.

Implementation Method 1

the first trench electrode can be used as a first capacitor electrode which forms a capacitor together with a second capacitor electrode disposed at the second side of the semiconductor body, in particular with the drain region in case of a common drain backside

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4481829A1Semiconductor die with a vertical transistor device
Publication Date: 2024.12.25 INFINEON TECH AUSTRIA AG
  • EP4481829A1 patent drawingFigure 1
  • EP4481829A1 patent drawingFigure 2
  • EP4481829A1 patent drawingFigure 3

AI summary

A semiconductor die (1) with a semiconductor body (15), the semiconductor die (1) comprising a transistor device (10) comprising a source region (11) at a first side (15.1) of the semiconductor body (15), a drain region (12) at a second side (15.2) of the semiconductor body (15), a trench (25) extending from the first side (15.1) into the semiconductor body (15) and having an elongated lateral extension, a first trench electrode (30) for a channel creation or field shaping, having an elongated lateral extension (35) and disposed in the trench (25), and a control electrode contact (31) contacting the first trench electrode (30) from the first side (15.1) of the semiconductor body (15) for applying an electrical potential, the control electrode contact (31) disposed at a first lateral position (41); and a sense electrode contact (32) contacting the first trench electrode (30) from the first side (15.1) of the semiconductor body (15) for sensing a voltage from the first trench electrode (30), wherein the sense electrode contact (32) is disposed at a second lateral position (42) which is spaced from the first lateral position (41).