Trench-Gate Transistor Structure for Bidirectional Voltage Blocking

Solution Overview

Problem

Existing electronic devices require two field-effect transistors in antiparallel to block both positive and negative voltages, which is bulky and costly.

Innovation Solution

An electronic device with transistors having gates contained in trenches in a semiconductor substrate, featuring doped semiconductor regions and buried wells, reducing surface area and manufacturing cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two field-effect transistors in antiparallel are used to block both positive and negative voltages, then the blocking capability is improved, but the surface area and manufacturing cost increase

Engineering Contradiction:

Improveblocking capabilityVSAvoidsurface area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent makes a single field-effect transistor perform multiple functions by enabling it to block both positive and negative drain-source voltages through specific doping configurations, eliminating the need for two separate transistors in antiparallel arrangement

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the functionality of two separate field-effect transistors into a single transistor structure by sharing common regions (drain, source, substrate) and using complementary doping in the well region to achieve bidirectional voltage blocking capability

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If two field-effect transistors in antiparallel are used to block both positive and negative voltages, then the blocking capability is improved, but the manufacturing cost increases

Engineering Contradiction:

Improveblocking capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent makes a single field-effect transistor perform multiple functions by enabling it to block both positive and negative drain-source voltages through specific doping configurations, eliminating the need for two separate transistors in antiparallel arrangement

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the functionality of two separate field-effect transistors into a single transistor structure by sharing common regions (drain, source, substrate) and using complementary doping in the well region to achieve bidirectional voltage blocking capability

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12593482B2Electronic device comprising transistors

Publication Date: 2026.03.31 STMICROELECTRONICS SRL

AI summary

The present disclosure relates to an electronic device comprising a semiconductor substrate and transistors having their gates contained in trenches extending in the semiconductor substrate, each transistor comprising a doped semiconductor well of a first conductivity type, the well being buried in the semiconductor substrate and in contact with two adjacent trenches among said trenches, a first doped semiconductor region of a second conductivity type, covering the well, in contact with the well, and in contact with the two adjacent trenches, a second doped semiconductor region of the second conductivity type more heavily doped than the first semiconductor region, extending in the first semiconductor region, and a third doped semiconductor region of the first conductivity type, more heavily doped than the well, covering the well, in contact with the first region, and extending in the semiconductor substrate in contact with the well.