Semiconductor Device With Embedded Trench Electrodes

Solution Overview

Problem

Semiconductor devices with a vertical electrode structure face challenges in achieving high breakdown voltage due to concentrated electric fields, which existing technologies struggle to address effectively.

Innovation Solution

A semiconductor device design featuring a field plate structure with embedded electrodes and n−-type diffusion regions in the trench bottom, which spreads the electric field distribution and reduces concentration, thereby increasing breakdown voltage without requiring optimal conditions for other factors like field insulating film thickness and embedded electrode length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a vertical electrode structure is used in a semiconductor device, then the device can achieve compact design and improved integration, but the electric field becomes concentrated leading to reduced breakdown voltage

Engineering Contradiction:

Improvedevice structure compactnessVSAvoidbreakdown voltage

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating an n−-type diffusion region with lower dopant concentration in the first semiconductor layer at the trench bottom. This localized modification of dopant concentration in a specific region (where the trench intersects the first semiconductor layer) alters the electric field distribution locally, reducing concentration without requiring changes to the overall vertical electrode structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the dopant concentration parameter by forming an n−-type diffusion region with lower concentration than the surrounding first semiconductor layer. This parameter change in the dopant concentration creates a controlled electric field distribution that prevents excessive concentration at the trench bottom, thereby increasing breakdown voltage while maintaining the compact vertical structure.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the dopant concentration in the first semiconductor layer is reduced to spread electric field, then breakdown voltage increases, but the region becomes too conductive affecting device operation

Engineering Contradiction:

Improvebreakdown voltageVSAvoiddopant concentration

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by creating an n−-type diffusion region with lower dopant concentration in the first semiconductor layer at the trench bottom. This localized modification of dopant concentration in a specific region (where the trench intersects the first semiconductor layer) alters the electric field distribution locally, reducing concentration without requiring changes to the overall vertical electrode structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the dopant concentration parameter by forming an n−-type diffusion region with lower concentration than the surrounding first semiconductor layer. This parameter change in the dopant concentration creates a controlled electric field distribution that prevents excessive concentration at the trench bottom, thereby increasing breakdown voltage while maintaining the compact vertical structure.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If field insulating film thickness and embedded electrode length are optimized to control electric field, then breakdown voltage increases, but manufacturing complexity and precision requirements increase

Engineering Contradiction:

Improvebreakdown voltageVSAvoidoptimization requirements

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the dopant concentration parameter by forming an n−-type diffusion region with lower concentration than the surrounding first semiconductor layer. This parameter change in the dopant concentration creates a controlled electric field distribution that prevents excessive concentration at the trench bottom, thereby increasing breakdown voltage while maintaining the compact vertical structure.

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

The design effectively raises breakdown voltage and enables high-speed switching by controlling electric field distribution through dopant concentration in n−-type diffusion layers, reducing the need for precise optimization of other factors.

Implementation Method 1

a first region (31) that is in contact with the insulating layer and at which a concentration of a first conductivity type dopant is lower than the concentration of the first conductivity type dopant at a second region (32) of the first semiconductor layer that is formed around the first region (31)

Methodology Applied

Scientific EffectElectric field distribution: Electric Field

Data Source

PatentUS9048215B2Semiconductor device having a high breakdown voltage

Publication Date: 2015.06.02 KK TOSHIBA

AI summary

A semiconductor device includes a first layer of a first-type, a second layer of a second-type formed on the first layer, a third layer of the first type formed on the second layer, a first electrode connected to the second and third layers, a second electrode connected to the first layer, a third electrode embedded in a trench formed through the third and second layers and into the first layer, a fourth electrode embedded in the trench below the third electrode, and an insulating layer formed in the trench around the fourth electrode. The first layer includes a first region that is in contact with the insulating layer and at which a concentration of the first-type dopant is lower than the concentration at a second region that is formed around the first region.