SiC Semiconductor Device Dopant Profile Optimization

Solution Overview

Problem

Silicon carbide (SiC) semiconductor devices face reliability issues due to various mechanisms during operation and manufacturing, affecting their performance and longevity.

Innovation Solution

The development of a semiconductor device with a specific dopant concentration profile in SiC semiconductor bodies, where a first semiconductor area with a higher dopant concentration forms a pn junction with a second area, optimizing electrical contact resistance and injection efficiency while minimizing dopant diffusion and recombination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pn junction is formed in SiC semiconductor body, then injection efficiency is improved, but dopant diffusion and recombination increase

Engineering Contradiction:

Improveinjection efficiencyVSAvoiddopant diffusion and recombination

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies local quality by creating distinct regions within the first semiconductor area with different dopant concentrations. A first part adjacent to the first surface has higher dopant concentration than a second part adjacent to the second semiconductor area, allowing optimized electrical contact at the surface while reducing dopant diffusion and recombination effects near the pn junction interface.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by varying the dopant concentration profile vertically through the first semiconductor area. The dopant concentration is higher in the first part near the first surface and lower in the second part near the pn junction, creating a gradient that balances electrical contact requirements with reduced dopant diffusion and recombination losses.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If dopant concentration is increased to improve electrical contact resistance, then contact quality improves, but dopant diffusion increases

Engineering Contradiction:

Improveelectrical contact resistanceVSAvoiddopant diffusion

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies local quality by creating distinct regions within the first semiconductor area with different dopant concentrations. A first part adjacent to the first surface has higher dopant concentration than a second part adjacent to the second semiconductor area, allowing optimized electrical contact at the surface while reducing dopant diffusion and recombination near the pn junction interface.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the first semiconductor area into at least two parts: a first part adjacent to the first surface with higher dopant concentration and a second part adjacent to the pn junction with lower dopant concentration. This segmentation allows independent optimization of electrical contact properties and dopant diffusion control.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11282926B2Semiconductor device with a semiconductor body of silicon carbide

Publication Date: 2022.03.22 INFINEON TECHNOLOGIES AG

AI summary

A semiconductor device includes a SiC body having a first semiconductor area of a first conductivity type and a second semiconductor area of a second conductivity type. The first semiconductor area is electrically contacted with a first surface of the SiC body and forms a pn junction with the second semiconductor area. The first and second semiconductor areas are arranged on one another in a vertical direction perpendicular to the first surface. The first semiconductor area has first and second dopant species. An average dopant concentration of the first dopant species in a first part of the first semiconductor area adjoining the first surface is greater than an average dopant concentration of the second dopant species. An average dopant concentration of the second dopant species in a second part of the first semiconductor area adjoining the second semiconductor area is greater than a dopant concentration of the first dopant species.