Vertical Semiconductor Die With Lateral Trench Gate Isolation

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Solution Overview

Problem

Existing semiconductor dies with vertical transistor devices face challenges in integrating lateral transistor devices effectively, particularly in achieving simplified junction isolation and optimized operational performance without complicating the standard process.

Innovation Solution

Incorporating a lateral transistor device into the same semiconductor body with a well region of opposite doping type, allowing for junction isolation and shared functionality with the vertical device, where the lateral device's gate electrode is formed in a vertical trench, enabling simplified integration and potential optimization of the vertical device's performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a lateral transistor device is integrated into the same semiconductor body with a vertical transistor device, then additional functionality and optimized operational performance are achieved, but the device complexity and manufacturing process complexity increase

Engineering Contradiction:
Improveadditional functionalityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines a lateral transistor device and a vertical transistor device into a single semiconductor body, sharing common structures such as the gate trench, body region, and source/drain regions. This merging approach enables additional functionality (lateral device operation) while reducing overall device complexity through shared components and simplified integration into standard CMOS processes

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a deep trench isolation is used between vertical and lateral devices, then junction isolation is achieved, but the manufacturing process complexity and difficulty increase

Engineering Contradiction:
Improvejunction isolationVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the isolation function from a complex deep trench isolation structure and implements it through a simpler well region structure. The lateral device is formed in a well region that provides natural junction isolation from the vertical device, eliminating the need for additional deep trench isolation steps and reducing manufacturing complexity while maintaining reliable electrical isolation

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If the gate electrode of the lateral device is formed in a vertical trench, then simplified integration into standard process is achieved, but the gate electrode structure becomes more complex

Engineering Contradiction:
Improvesimplified integrationVSAvoidgate electrode structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent creates a multi-functional gate trench structure that serves both the lateral and vertical transistor devices. The same gate trench accommodates the lateral device's gate electrode and provides the vertical device's gate structure, enabling simplified integration into standard CMOS processes while the vertical trench geometry optimizes the gate electrode's electrical performance and control characteristics

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

4Reliability

If the source and drain regions are arranged at opposite sides of the semiconductor body for vertical current flow, then high breakdown voltage is achieved, but the device area increases

Engineering Contradiction:
Improvebreakdown voltageVSAvoiddevice area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent transitions from a planar arrangement to a three-dimensional vertical structure, arranging source and drain regions at opposite sides of the semiconductor body along the vertical dimension. This vertical configuration achieves high breakdown voltage through increased charge carrier path length while minimizing the lateral device area, as the current flow occurs primarily in the vertical direction through the thin semiconductor body

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 approach allows for enhanced operational performance of the vertical device by enabling junction isolation and simplified integration, reducing the complexity of the manufacturing process and potentially improving breakdown voltage and on-resistance.

Implementation Method 1

the lateral device is embedded into a well region made of a second doping type opposite to the source and drain doping of the vertical device

Methodology Applied
Scientific EffectJunction isolation: Electrical Resistance

Data Source

PatentEP4481821A1Semiconductor die with a vertical transistor device
Publication Date: 2024.12.25 INFINEON TECH AUSTRIA AG
  • EP4481821A1 patent drawingFigure 1
  • EP4481821A1 patent drawingFigure 2
  • EP4481821A1 patent drawingFigure 3a~3b

AI summary

The disclosure relates to a semiconductor die (1) with a semiconductor body (15), the semiconductor die (1) comprising a vertical transistor device (10), the vertical transistor device (10) having a source region (11) and a drain region (12) at opposite sides (15.1, 15.2) of the semiconductor body (15); the source region (11) and the drain region (12) made of a first doping type; the semiconductor die (1) further comprising a lateral transistor device (50), the lateral transistor device (50) having a source region (51) and a drain region (52) at the same side (15.1) of the semiconductor body (15); a body region (53) laterally between the source region (51) and the drain region (52); and a gate electrode (56); wherein the gate electrode (56) of the lateral transistor device (50) is disposed in a gate trench (59) laterally aside the body (53) region, and wherein the lateral transistor device (50) is disposed in a well region (60), the well (60) region made of a second doping type opposite to the first doping type.