SOI Wafer Structure Using LaAlO3 BOX and SrTiO3 Buffer

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Solution Overview

Problem

Traditional silicon-on-insulator (SOI) wafer fabrication processes are complex, energy-intensive, and limited to using SiO2 as the buried oxide layer, excluding integration of other materials and requiring costly methods like SIMOX or wafer bonding.

Innovation Solution

Epitaxial integration of a device silicon layer on insulating LaAlO3, facilitated by a thin SrTiO3 buffer layer, allowing direct deposition techniques and incorporation of alternative BOX materials, such as LaAlO3, via thin film deposition methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional SIMOX or wafer bonding processes are used to fabricate SOI wafers, then the buried oxide layer can be formed, but the process complexity and energy consumption increase significantly

Engineering Contradiction:

ImproveSOI wafer fabricationVSAvoidfabrication process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A thin SrTiO3 buffer layer is introduced as an intermediary between the silicon substrate and the LaAlO3 buried oxide layer. This buffer layer facilitates epitaxial growth and enables the integration of alternative oxide materials, simplifying the overall fabrication process while maintaining structural integrity and electrical performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the material parameters by replacing traditional SiO2 buried oxide with LaAlO3 and introducing SrTiO3 as a buffer layer. This parameter change enables direct thin film deposition techniques, reducing process complexity and energy consumption while allowing integration of diverse functional oxides

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If traditional SiO2 buried oxide is used in SOI wafers, then the structure is stable, but the adaptability to integrate other materials is limited

Engineering Contradiction:

Improveburied oxide layerVSAvoidmaterial integration

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The SrTiO3 buffer layer serves multiple functions: it provides a stable interface with the silicon substrate, enables epitaxial growth of LaAlO3, and allows integration of various functional oxides. This multi-functional approach enhances material adaptability while maintaining structural stability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs a composite structure combining SrTiO3 buffer layer, LaAlO3 buried oxide, and silicon device layer. This composite material system integrates the stability of traditional silicon-based structures with the versatility of perovskite oxides, enabling both structural integrity and diverse material integration

Inventive Principle:

Principle #40Composite materials

3Productivity

If SIMOX or wafer bonding processes are used, then SOI wafers can be produced, but energy consumption increases

Engineering Contradiction:

ImproveSOI wafer productionVSAvoidfabrication process

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent replaces mechanical processes (wafer bonding, ion implantation in SIMOX) with direct epitaxial thin film deposition techniques. This substitution reduces energy consumption by eliminating high-temperature bonding steps and ion acceleration processes, while maintaining production capability through controlled vapor-phase deposition

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Simplifies SOI wafer production, enables integration of diverse functional oxides, and opens possibilities for novel devices with enhanced device density and integration of perovskite transition metal oxides, facilitating 3D integration and reducing energy consumption.

Implementation Method 1

epitaxial integration of a device silicon layer on insulating LaAlO3, which is itself epitaxially integrated on a silicon (001) substrate

Methodology Applied

Scientific EffectEpitaxy: Epitaxy

Implementation Method 2

direct thin film deposition techniques

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentUS12471367B2Systems and techniques for forming silicon-on-oxide-on-silicon structures

Publication Date: 2025.11.11 BOARD OF RGT THE UNIV OF TEXAS SYST

AI summary

Some embodiments of the present technology simplify the process of producing SOI wafers significantly compared to traditional methods. Furthermore, various embodiments provide a route for the integration of perovskite transition metal oxide thin films with different properties into SOI wafers. As such films display a wide array of novel electronic, magnetic, and optical phenomena, their integration into technologically-relevant SOI wafers will likely allow for the construction of a wide array of novel devices.