Semiconductor Electrode Equipotential Design for Breakdown Prevention

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Solution Overview

Problem

Semiconductor devices, such as MOSFETs, face reliability issues due to dielectric breakdown and leakage currents in the insulating portions, particularly when high voltages are applied repeatedly, leading to time-dependent dielectric breakdown and reduced productivity in manufacturing processes.

Innovation Solution

The semiconductor device design includes a U-shaped electrode configuration with a specific insulating layer structure, where the second electrode is electrically connected to the source electrode rather than the gate pad, reducing potential differences and electric field concentrations, thereby enhancing the breakdown voltage and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the second electrode is connected to the gate pad, then the gate control function is achieved, but dielectric breakdown and leakage currents occur in the insulating portions due to voltage gradients

Engineering Contradiction:

Improvebreakdown voltageVSAvoiddielectric breakdown and leakage currents

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The second electrode is electrically connected to the source electrode instead of the gate pad, making the second electrode and source electrode equipotential. This eliminates voltage gradients across the insulating portions between these electrodes, preventing dielectric breakdown and leakage currents while maintaining reliable high-voltage operation

Inventive Principle:

Principle #12Equipotentiality

2Productivity

If conventional electrode configurations are used, then manufacturing processes are simpler, but productivity is reduced due to rework from dielectric breakdown

Engineering Contradiction:

Improvemanufacturing productivityVSAvoiddevice reliability under repeated high voltage

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The electrode configuration is designed in advance with the second electrode connected to the source electrode, preemptively eliminating voltage gradients and preventing dielectric breakdown before it occurs. This preliminary design prevents manufacturing rework and maintains high productivity while ensuring device reliability

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9842924B2Semiconductor device having an electrode that is in a peripheral trench region and at a same potential as a source electrode

Publication Date: 2017.12.12 KK TOSHIBA

AI summary

A semiconductor device includes a layer having first and second surfaces, a first region including central and peripheral portions, and a second region on the first region. First trenches extend into the first surface and terminate within the first region in the central portion. Each first trench includes a first electrode and a gate electrode over the first electrode. The first and gate electrodes are spaced from the first and second regions by a first insulating layer. A second trench extends into the first surface and terminates within the first region in the peripheral portion. The second trench includes a second electrode and a third electrode over the second electrode. The second and third electrodes are spaced from the first and second regions by a second insulating layer. A fourth electrode overlies the first insulating layer in the central portion and the second insulating layer in the peripheral portion.