Auxiliary Gate Electrode Layout for ESD-Resistant Semiconductor Cells

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Solution Overview

Problem

Existing semiconductor devices face challenges in maintaining electrostatic breakdown resistance and ON resistance characteristics while minimizing layout changes due to the integration of auxiliary electrodes.

Innovation Solution

The semiconductor device incorporates an auxiliary electrode embedded in a recess portion of the semiconductor layer via an insulating film, electrically connected to a control electrode through a second electrode layer, enhancing parasitic capacitance and electrostatic breakdown resistance without affecting the cell structure layout.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the auxiliary electrode is embedded in the first recess portion via the second insulating film, then electrostatic breakdown resistance is improved, but device complexity increases

Engineering Contradiction:

Improveelectrostatic breakdown resistanceVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The auxiliary electrode is embedded within the first recess portion, creating a nested structure where the electrode is housed inside the recess. This nesting approach increases electrostatic breakdown resistance by providing physical protection and proper electrical isolation through the second insulating film, while maintaining a compact design that limits overall complexity growth.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The second insulating film serves as an intermediary layer between the auxiliary electrode and the first recess portion. This intermediary structure enables proper electrical isolation and capacitance formation, improving electrostatic breakdown resistance by preventing direct contact and allowing controlled electrical fields to develop between the electrode and surrounding structures.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the auxiliary electrode is formed separately from the cell structure, then ON resistance characteristics are maintained, but manufacturing precision requirements increase

Engineering Contradiction:

ImproveON resistance characteristicsVSAvoidmanufacturing precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The auxiliary electrode is formed as a separate structure from the cell structure, dividing the device into distinct functional regions. This segmentation maintains ON resistance characteristics by preventing interference between the auxiliary electrode and active cell regions, while allowing independent optimization of each component's manufacturing parameters.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first recess portion is specifically positioned and dimensioned to create appropriate electrical characteristics only in the local region where the auxiliary electrode is embedded. This localized approach maintains ON resistance characteristics in the active regions while providing enhanced electrostatic protection in specific areas, reducing the impact on overall manufacturing precision requirements.

Inventive Principle:

Principle #3Local quality

3Reliability

If the auxiliary electrode increases parasitic capacitance, then electrostatic breakdown resistance is improved, but loss of energy increases

Engineering Contradiction:

Improveelectrostatic breakdown resistanceVSAvoidloss of energy

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The auxiliary electrode's capacitance parameters are carefully controlled through its geometric dimensions and positioning within the first recess portion. By adjusting these parameters, the design achieves sufficient parasitic capacitance to improve electrostatic breakdown resistance while limiting excessive capacitance that would cause significant energy loss during switching operations.

Inventive Principle:

Principle #35Parameter changes

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 increases electrostatic breakdown resistance and maintains ON resistance characteristics by embedding the auxiliary electrode, thereby providing improved electrostatic breakdown resistance and preventing layout changes.

Implementation Method 1

increases electrostatic capacitance and parasitic capacitance between electrode layers

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Implementation Method 2

increases electrostatic capacitance and parasitic capacitance between electrode layers

Methodology Applied

Scientific EffectParasitic capacitance: Parasitic Capacitance

Implementation Method 3

suppressing electric field concentration

Methodology Applied

Scientific EffectElectric field: Electric Field

Data Source

PatentUS12604491B2Semiconductor device including auxiliary electrode that is electrically connected to a control electrode via a second electrode layer

Publication Date: 2026.04.14 ROHM CO LTD

AI summary

A semiconductor device includes a semiconductor layer, a first conductive type first region formed in a surface layer portion of a first principal surface of the semiconductor layer, a cell structure having a second conductive type second region formed in a surface layer portion of the first region, a first conductive type third region formed in the surface layer portion of the first region such that third region is in contact with the second region, and a control electrode opposing the second region via a first insulating film adjacent to the second region, the control electrode forming a current path in the second region, a first electrode layer formed on the first principal surface such that the first electrode layer covers the cell structure, and electrically connected to the third region, a second electrode layer formed on the first principal surface separately from the first electrode layer.