Power Semiconductor Two-Stage Doping Profile

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Solution Overview

Problem

Existing power semiconductor components face challenges in achieving low blocking currents and low on-state and switching losses, particularly in their production processes which often require complex irradiation methods and multi-stage doping profiles, making them difficult to produce simply and efficiently.

Innovation Solution

A power semiconductor component with a base body of monocrystalline silicon featuring a trough-shaped region with a two-stage doping profile and an edge structure of field rings with a single-stage doping profile, along with a field plate structure and passivation layers, allowing for reduced penetration depths and optimized dopant concentrations for improved electrical conductivity and reduced manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a two-stage doping profile with deep diffusion and extensive grinding is used, then blocking currents are reduced, but manufacturing complexity increases

Engineering Contradiction:
Improveblocking currentsVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The doping profile is segmented into two distinct stages: a first deep diffusion creating a deep doping profile, and a second shallow diffusion creating a surface doping profile. This segmentation allows each stage to be optimized independently, achieving low blocking currents through the deep profile while maintaining simple manufacturing by avoiding extensive grinding steps

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first deep diffusion is performed as a preliminary action to create the deep doping profile before the second shallow diffusion. This preliminary deep diffusion establishes the foundation for low blocking currents, and the subsequent shallow diffusion merely adds surface doping without requiring intermediate grinding, thus simplifying the overall manufacturing process

Inventive Principle:
Principle #10Preliminary action

2Loss of energy

If particle irradiation is used to improve switching behavior, then switching losses are reduced, but manufacturing complexity increases

Engineering Contradiction:
Improveswitching lossesVSAvoidmanufacturing complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The invention replaces expensive and complex particle irradiation processes with conventional thermal diffusion processes using dopant materials. The dopant atoms serve as a simpler, more accessible alternative to particle irradiation, achieving similar switching improvement without the need for specialized irradiation equipment and procedures

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the approach from physical particle irradiation to chemical dopant diffusion by controlling diffusion parameters such as temperature, time, and dopant concentration. This parameter-based approach using thermal diffusion achieves switching behavior improvement through controlled dopant distribution rather than particle bombardment

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 solution enables a simple production process with low blocking currents and switching losses, enhancing the component's performance as a flow control valve, such as a diode, by maintaining low electrical resistance and efficient voltage handling without the need for particle irradiation.

Implementation Method 1

a first two-stage doping profile (100) with a first penetration depth (102) from the first main surface (6) into the base body (2)

Methodology Applied
Scientific EffectDoping: Dopants

Data Source

PatentEP2398057B8High performance semi-conductor element with two stage doping profile
Publication Date: 2019.11.20 SEMIKRON DANFOSS ELEKTRONIK GMBH & CO KG

AI summary

The component (1) has a horizontally centered tub-shaped section (10) arranged in a main body (2). A passivation layer (32) is arranged between a set of body parts (42). Another set of body parts (44) is laterally spaced from the main body and horizontally projected above a field ring (20) along direction of an edge of the component. The body parts are formed on a conductive form body (40). Another passivation layer (34) is arranged above the former passivation layer. A layer of silicon nitride is arranged between the passivation layers.