High-Voltage Semiconductor Isolation Pillars and Composite Substrates

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Solution Overview

Problem

Conventional high-voltage semiconductor structures face challenges in achieving optimal electrical isolation and voltage withstanding capabilities, especially at high temperatures, which affects the performance and reliability of high-frequency, high-power semiconductor devices like high electron mobility transistors.

Innovation Solution

A high-voltage semiconductor structure is designed with a substrate comprising a core layer and a composite material layer, featuring a semiconductor channel layer, a barrier layer, a cap layer, a doped isolation region, and isolation pillars that penetrate through the layers to provide enhanced electrical isolation and improved voltage handling capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional semiconductor structures are used, then manufacturing simplicity is maintained, but electrical isolation and voltage withstanding capabilities are insufficient

Engineering Contradiction:

Improveelectrical isolation capabilityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The isolation structure is divided into multiple segments: a doped isolation region within the semiconductor layers and separate isolation pillars extending through the composite material layer. This segmentation allows each component to contribute to electrical isolation independently, achieving superior isolation capability while maintaining a systematic approach to structure design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The isolation pillars act as intermediary elements that physically and electrically separate adjacent high-voltage semiconductor devices. These pillars extend through the composite material layer and make contact with the doped isolation region, creating an intermediate isolation barrier that prevents direct electrical interference between devices.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If conventional isolation structures are used, then device complexity is low, but voltage withstanding capability at high temperatures deteriorates

Engineering Contradiction:

Improvevoltage withstanding capabilityVSAvoidisolation structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The substrate employs a composite material layer comprising multiple materials with different properties, including a first material and a second material with different thermal and electrical characteristics. This composite structure enhances voltage withstanding capability by utilizing the complementary properties of different materials, particularly at high temperatures where thermal management becomes critical.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The isolation pillars extend vertically through the composite material layer in the depth dimension, creating a three-dimensional isolation architecture. This vertical dimension adds isolation capability without increasing lateral device footprint, allowing voltage withstanding enhancement while maintaining compact device layout.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If isolation pillars penetrate through composite material layer, then electrical isolation is enhanced, but manufacturing complexity increases

Engineering Contradiction:

Improveelectrical isolation effectivenessVSAvoidfabrication complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The doped isolation region is formed within the semiconductor channel and barrier layers before the isolation pillars are fabricated. This preliminary doping action creates a foundation that guides subsequent pillar formation, allowing the pillars to be aligned and integrated more easily during later fabrication steps, thereby reducing overall manufacturing complexity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The isolation pillars serve multiple functions simultaneously: they provide electrical isolation between devices, act as mechanical support structures through the composite material layer, and serve as alignment references for subsequent fabrication steps. This multi-functionality reduces the need for separate dedicated structures, simplifying the overall manufacturing process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11552188B2High-voltage semiconductor structure

Publication Date: 2023.01.10 VANGUARD INTERNATIONAL SEMICONDUCTOR CORPORATION

AI summary

A semiconductor structure includes a substrate, a semiconductor epitaxial layer, a semiconductor barrier layer, a first semiconductor device, a doped isolation region, and at least one isolation pillar. The substrate includes a core layer and a composite material layer, the semiconductor epitaxial layer is disposed on the substrate, and the semiconductor barrier layer is disposed on the semiconductor epitaxial layer. The first semiconductor device is disposed on the substrate, where the first semiconductor device includes a first semiconductor cap layer disposed on the semiconductor barrier layer. The doped isolation region is disposed at one side of the first semiconductor device. At least a portion of the isolation pillar is disposed in the doped isolation region, and the isolation pillar surrounds at least a portion of the first semiconductor device and penetrates the composite material layer.