Schottky Junction Moisture Protection via Barrier Metal Layer

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Solution Overview

Problem

Despite protective films, moisture can still enter the Schottky junction in semiconductor devices, contaminating the interface and corroding the Schottky electrode, which reduces the reliability and characteristics of the device.

Innovation Solution

A semiconductor device with a barrier metal layer that forms ohmic contact around the Schottky electrode, covering its side surface and preventing moisture from reaching the junction, while also suppressing metal diffusion between electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protective film (silicon oxide, silicon nitride, organic insulating film) is laminated onto the Schottky electrode, then moisture entry is suppressed, but moisture can still enter through spaces between the thermal oxide film and CVD insulating film, contaminating the Schottky junction interface and corroding the Schottky electrode

Engineering Contradiction:

Improveprotection of Schottky junctionVSAvoidmoisture entry

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention transitions from a planar protective film structure to a three-dimensional barrier metal layer structure that wraps around the Schottky electrode. The barrier metal layer extends from the front surface through the side surface to the rear surface, creating a multi-dimensional barrier that blocks moisture entry paths that penetrate through or around the laminated protective film structure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The barrier metal layer acts as an intermediary protective element between the external environment and the Schottky electrode. It provides an additional protective interface that prevents direct contact between moisture and the Schottky electrode, supplementing the protective function of the laminated insulating films.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a laminated protective film structure is used, then the Schottky electrode is protected, but the structure complexity increases and manufacturing difficulty arises

Engineering Contradiction:

Improveprotection of Schottky electrodeVSAvoidprotective film structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protective function is segmented into two distinct components: the laminated insulating film structure for general protection and the barrier metal layer for targeted moisture blocking. This segmentation allows each component to perform its specific protective function optimally without requiring the entire structure to be overly complex.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The barrier metal layer is strategically positioned at critical locations where moisture entry is most likely to occur (around the Schottky electrode from front, side, and rear surfaces). This localized enhancement provides targeted protection without requiring complex modifications to the entire device structure.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If the Schottky electrode is exposed to moisture, then the interface between Schottky electrode and semiconductor substrate is contaminated and the Schottky electrode is corroded, but adding protective structures increases manufacturing complexity

Engineering Contradiction:

Improvecontamination and corrosionVSAvoidmanufacturing process

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The barrier metal layer is formed in advance during the manufacturing process, creating a pre-established moisture barrier before final assembly and testing. This preliminary protective action ensures that the Schottky electrode is protected from the outset, preventing contamination and corrosion issues that would require complex post-manufacturing repairs.

Inventive Principle:

Principle #10Preliminary action

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

The barrier metal layer effectively prevents moisture and metal diffusion, enhancing the reliability and characteristics of the semiconductor device by protecting the Schottky junction and electrode from contamination and corrosion.

Implementation Method 1

a barrier metal layer that is in ohmic contact with the first main surface around the Schottky electrode

Methodology Applied

Scientific EffectOhmic contact: Conduction (electrical)

Implementation Method 2

a barrier metal layer that is in ohmic contact with the first main surface around the Schottky electrode and covers a side surface of the Schottky electrode

Methodology Applied

Scientific EffectPhysical barrier: Physical Containment

Implementation Method 3

The barrier metal layer effectively prevents moisture and metal diffusion

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS9941124B1Semiconductor device

Publication Date: 2018.04.10 SANKEN ELECTRIC CO LTD

AI summary

A semiconductor device includes a semiconductor base body having a first main surface and a second main surface, the first main surface and the second main surface being opposite with each other; a Schottky electrode that is disposed on the first main surface and forms a Schottky junction with the semiconductor base body; and a barrier metal layer that is brought into ohmic contact with the first main surface around the Schottky electrode and covers a side surface of the Schottky electrode.