Low-Temperature Recrystallization of Semiconductor Layers

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for transferring a monocrystalline semiconductor layer onto a support substrate often result in crystalline defects due to embrittlement implantation, which deteriorate the electrical properties of the layer, and require high-temperature heat treatments that are not always feasible, especially when the substrate contains electronic devices or metal zones.

Innovation Solution

A method involving the amorphization of a surface portion of the monocrystalline layer without disorganizing the underlying portion, followed by recrystallization at a temperature below 500 °C using solid-phase epitaxy, to remove crystalline defects and reactivate dopants, while maintaining the integrity of the support substrate and doped regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high-temperature heat treatment (>800°C) is applied to heal crystalline defects, then the crystalline quality of the semiconductor layer is restored, but electronic devices and metal zones on the support substrate are damaged

Engineering Contradiction:

Improvecrystalline qualityVSAvoiddamage to electronic devices and metal zones

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating an amorphous layer specifically in the region requiring defect healing, while preserving the crystalline structure in other regions. The amorphous layer is formed by ion implantation localized to the semiconductor layer, and subsequent recrystallization occurs only in this localized region through solid-phase epitaxy at low temperature, avoiding damage to electronic devices and metal zones while restoring crystalline quality where needed.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the temperature parameter from conventional high-temperature (>800°C) heat treatment to low-temperature (<500°C) processing. This parameter change enables defect healing through solid-phase epitaxy of the amorphous layer without damaging temperature-sensitive components. The process transforms the thermal regime entirely, allowing crystalline restoration at temperatures safe for electronic devices and metal interconnections.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If embrittlement implantation is used to transfer the semiconductor layer, then the layer transfer is enabled, but crystalline defects are created that deteriorate electrical properties

Engineering Contradiction:

Improvelayer transfer capabilityVSAvoidcrystalline quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent converts the harm of ion implantation into a benefit by using the same ion implantation technique to create an amorphous layer that will subsequently be recrystallized. The implantation damage that initially degrades crystalline quality is transformed into a controlled amorphous structure that, when recrystallized through solid-phase epitaxy, produces a defect-free crystalline layer. Thus, the harmful implantation effect becomes the foundation for achieving superior crystalline quality.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent utilizes phase transitions by transforming the semiconductor layer from crystalline to amorphous through ion implantation, then from amorphous back to crystalline through solid-phase epitaxy at low temperature. This phase transition cycle allows the material to be restructured and healed without high-temperature processing. The controlled transition through the amorphous phase enables defect elimination while preserving the benefits of layer transfer.

Inventive Principle:

Principle #36Phase transitions

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 approach effectively heals the transferred semiconductor layer, restoring its initial electrical properties without the need for high-temperature treatments, ensuring the semiconductor layer's quality and functionality, even when integrated with electronic devices or metal zones.

Implementation Method 1

recrystallization being carried out at a temperature below 500 °C

Methodology Applied

Scientific EffectSolid-phase epitaxy: Epitaxy

Implementation Method 2

The first portion of the monocrystalline layer to be transferred is rendered amorphous... followed by recrystallization

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentEP2551897B1Method for transferring a monocrystalline semiconductor layer onto a support substrate

Publication Date: 2017.10.11 SOITEC SA

Figure 1~2B
Figure 2C~2E
Figure 2F~3

AI summary

The invention relates to a method for transferring a monocrystalline semiconductor layer (3) onto a support substrate (1), comprising the following steps: (a) implanting species in a donor substrate (31); (b) bonding the donor substrate (31) to said support substrate (1); (c) fracturing the donor substrate (31) to transfer the layer (3) onto the support substrate (1); and steps wherein: • a portion (34) of the monocrystalline layer (3) to be transferred is rendered amorphous, without disorganizing the crystal lattice of a second portion (35) of said layer (3), said portions (34, 35) being, respectively, a surface portion and a buried portion of the monocrystalline layer (3); • said amorphous portion (34) is recrystallized at a temperature below 500 °C, the crystal lattice of said second portion (35) serving as a seed for recrystallization.