Porous Semiconductor Separation Layer for Dopant Diffusion Control

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Solution Overview

Problem

Existing methods for forming semiconductor devices face challenges in achieving improved dopant distribution and controlling dopant diffusion during the separation of semiconductor devices from substrates.

Innovation Solution

A method involving the formation of a first semiconductor layer with a higher dopant concentration than the substrate, increasing its porosity, and first annealing at a temperature of at least 1050° C, followed by the separation of a second semiconductor layer from the substrate within the first semiconductor layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a porous Si separation layer is formed and an active Si layer is epitaxially grown, then semiconductor devices can be separated from substrate, but accurate control of thickness and dopant distribution becomes difficult

Engineering Contradiction:

Improvethickness control of separation layerVSAvoidcomplexity of separation process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the key parameter of dopant concentration in the first semiconductor layer. By forming a first semiconductor layer with higher dopant concentration than the substrate, and then increasing its porosity followed by high-temperature annealing, the method achieves precise control over dopant distribution and layer thickness during separation, resolving the contradiction between manufacturing precision and process complexity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary actions by forming the first semiconductor layer with controlled dopant concentration and increasing its porosity before the actual separation process. The high-temperature annealing is performed in advance to establish the desired dopant distribution, which then facilitates controlled separation when the second semiconductor layer is formed, reducing the complexity of the separation step itself.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If dopant concentration is increased in the first semiconductor layer, then dopant distribution is improved, but dopant diffusion during thermal processing increases

Engineering Contradiction:

Improvedopant distribution controlVSAvoiddopant diffusion

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating a first semiconductor layer with locally higher dopant concentration compared to the substrate. This localized high dopant concentration region is then selectively transformed into a porous structure and annealed, allowing precise control of dopant distribution in specific areas without causing uncontrolled diffusion throughout the entire structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes porous materials by increasing the porosity of the first semiconductor layer before annealing. This porous structure modifies the dopant distribution characteristics and controls dopant diffusion behavior during subsequent high-temperature processing, allowing the harmful effect of diffusion to be managed while maintaining improved dopant distribution.

Inventive Principle:

Principle #31Porous materials

3Manufacturing precision

If high temperature annealing is performed to control dopant distribution, then manufacturing precision improves, but energy consumption and process time increase

Engineering Contradiction:

Improvedopant distribution controlVSAvoidenergy consumption of annealing process

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent performs preliminary porosity enhancement on the first semiconductor layer before the high-temperature annealing step. This preliminary action modifies the material structure to facilitate more efficient dopant distribution control during annealing, potentially reducing the required annealing time and energy consumption while maintaining manufacturing precision.

Inventive Principle:

Principle #10Preliminary action

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 method enhances dopant distribution and reduces dopant diffusion, allowing for improved control and efficiency in the formation of semiconductor devices.

Implementation Method 1

first annealing the first semiconductor layer at a temperature of at least 1050° C.

Methodology Applied

Scientific EffectThermal diffusion: Diffusion

Implementation Method 2

increasing the porosity of the first semiconductor layer

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS12211703B2Methods for forming a semiconductor device having a second semiconductor layer on a first semiconductor layer

Publication Date: 2025.01.28 INFINEON TECHNOLOGIES AG

AI summary

A method of forming a semiconductor device includes: forming a first semiconductor layer on a semiconductor substrate, the first semiconductor layer being of the same dopant type as the semiconductor substrate, the first semiconductor layer having a higher dopant concentration than the semiconductor substrate; increasing the porosity of the first semiconductor layer; first annealing the first semiconductor layer in an atmosphere including an inert gas; forming a second semiconductor layer on the first semiconductor layer; and separating the second semiconductor layer from the semiconductor substrate by splitting within the first semiconductor layer. Additional methods of forming a semiconductor device are described.