Semiconductor Structure With Two-Stage Accumulation and Lifetime Control

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Solution Overview

Problem

Existing semiconductor devices face challenges in achieving optimal performance due to limitations in carrier injection enhancement and ON-voltage reduction, while also maintaining robust withstand capabilities against latch-up, short-circuit, and RBSOA.

Innovation Solution

The semiconductor device incorporates a two-stage accumulation region with specific doping concentrations and a lifetime control region on both the front and back surfaces of the semiconductor substrate, optimizing the carrier injection enhancement effect and improving withstand capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single-stage accumulation region is used, then the structure is simple, but the carrier injection enhancement effect is insufficient and ON-voltage reduction is limited

Engineering Contradiction:

Improvecarrier injection enhancement effectVSAvoidaccumulation region structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The accumulation region is divided into two distinct stages: a first accumulation region with higher doping concentration and a second accumulation region with lower doping concentration. This segmentation allows each stage to contribute differently to carrier injection, enhancing the overall effect while enabling optimization of ON-voltage without excessive complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the accumulation structure are assigned different doping concentrations tailored to their specific functions. The first accumulation region uses higher doping for strong carrier injection, while the second uses lower doping for sustained effect, creating local quality variations that optimize performance

Inventive Principle:

Principle #3Local quality

2Reliability

If multiple lifetime control regions are added to improve withstand capabilities, then reliability against latch-up and short-circuit improves, but the manufacturing process becomes more complex

Engineering Contradiction:

Improvewithstand capability against latch-up and short-circuitVSAvoidlifetime control region structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Lifetime control regions are integrated into the existing accumulation region structure rather than being added as separate components. The lifetime control regions are formed in conjunction with the first and second accumulation regions, merging multiple functions into a unified structure that improves reliability without proportionally increasing complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The accumulation region structure serves multiple functions simultaneously: it provides carrier injection enhancement, voltage reduction, and lifetime control for latch-up and short-circuit protection. This multi-functionality reduces the need for separate dedicated structures, balancing reliability improvement with manufacturing complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Manufacturing precision

If precise mask alignment is used to form accumulation regions, then doping precision improves, but manufacturing complexity and potential mask deviations increase

Engineering Contradiction:

Improvedoping precision of accumulation regionVSAvoidmask alignment process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

A stop layer is formed beforehand at the desired depth position before creating the accumulation regions. This preliminary structure serves as a physical reference that guides subsequent doping processes, ensuring precise depth control without requiring complex mask alignment procedures

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The stop layer acts as an intermediary reference structure that mediates between the doping process and the final accumulation region formation. By providing a tangible depth marker, it simplifies the doping process and reduces reliance on complex mask alignment while maintaining high precision

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This configuration enhances the carrier injection enhancement effect, reduces the ON-voltage of the transistor portion, and improves the semiconductor device's withstand capabilities against latch-up, short-circuit, and RBSOA, while avoiding mask deviations and simplifying the manufacturing process.

Implementation Method 1

a lifetime control region on both the front surface and the back surface of the semiconductor substrate, thereby optimizing the carrier injection enhancement effect and improving withstand capabilities

Methodology Applied

Scientific EffectCarrier lifetime control:

Implementation Method 2

The semiconductor device includes a first accumulation region and a second accumulation region, both provided in an epitaxial layer

Methodology Applied

Scientific EffectDoping: Dopants

Data Source

PatentUS12283608B2Semiconductor device and manufacturing method of the same

Publication Date: 2025.04.22 FUJI ELECTRIC CO LTD

AI summary

Provided is a semiconductor device having a transistor portion and a diode portion, including: a drift region of a first conductivity type provided in a semiconductor substrate; an accumulation region of a first conductivity type provided on a front surface side of the semiconductor substrate with respect to the drift region in the transistor portion and the diode portion; and a first lifetime control region provided on the front surface side of the semiconductor substrate in the transistor portion and the diode portion.