Horizontal Flow Reactor Central Injector for Single Crystal Piezoelectric Films

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Solution Overview

Problem

Existing bulk acoustic wave resonator devices using polycrystalline piezoelectric thin films face challenges at frequencies above 5 GHz due to reduced crystallinity, which affects their performance in wireless data communication applications.

Innovation Solution

The use of low-vapor pressure metalorganic precursors in CVD systems to form single crystal piezoelectric layers, incorporating dopants like Scandium and Yttrium, heated to high temperatures to enhance crystallinity and improve device performance at higher frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polycrystalline piezoelectric thin films are used in bulk acoustic wave resonators, then the devices can be manufactured with existing fabrication processes, but the crystallinity is reduced at frequencies above 5 GHz, degrading device performance

Engineering Contradiction:

ImprovemanufacturabilityVSAvoidcrystallinity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the deposition parameters by using low-vapor pressure metalorganic precursors with CVD at elevated temperatures (600-800°C), which fundamentally alters the film formation process to achieve single crystal structures instead of polycrystalline, thereby resolving the crystallinity issue at high frequencies

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material strategies by using metalorganic precursor compounds containing specific metal elements (such as scandium, yttrium, or lithium) combined with organic ligands, which decompose during CVD to form pure piezoelectric single crystal layers with controlled composition and enhanced crystallinity

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If low-vapor pressure metalorganic precursors are heated to high temperatures (600-800°C) to form single crystal layers, then crystallinity is improved for high-frequency operation, but the process complexity and equipment requirements increase

Engineering Contradiction:

ImprovecrystallinityVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses metalorganic precursor compounds as intermediaries that can be delivered through heated lines at controlled temperatures, then decompose in the reactor chamber to form single crystal layers, serving as a bridge between the need for high temperature processing and the requirement for precise compositional control

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional physical vapor deposition or sputtering methods with chemical vapor deposition using metalorganic precursors, substituting mechanical/physical processes with a chemically-controlled deposition mechanism that enables single crystal formation at controlled temperatures

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

This approach enables the formation of high-quality single crystal piezoelectric layers, enhancing the performance of bulk acoustic wave resonator devices for frequencies above 5 GHz, thereby addressing the limitations of polycrystalline-based films.

Implementation Method 1

heating it to a temperature sufficient to vaporize the low vapor pressure metalorganic precursor and deliver the vapor to the reactor chamber

Methodology Applied

Scientific EffectVaporization: Evaporation

Implementation Method 2

low-vapor pressure metalorganic precursors in CVD systems to form single crystal piezoelectric layers

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Data Source

PatentUS11618968B2Apparatus including horizontal flow reactor with a central injector column having separate conduits for low-vapor pressure metalorganic precursors and other precursors for formation of piezoelectric layers on wafers

Publication Date: 2023.04.04 AKOUSTIS TECHNOLOGIES CORP

AI summary

An apparatus for forming semiconductor films can include a horizontal flow reactor including an upper portion and a lower portion that are moveably coupled to one another so as to separate from one another in an open position and so as to mate together in a closed position to form a reactor chamber. A central injector column can penetrate through the upper portion of the horizontal flow reactor into the reactor chamber, the central injector column configured to allow metalorganic precursors into the reactor chamber in the closed position. A heated metalorganic precursor line can be coupled to the central injector column and configured to heat a low vapor pressure metalorganic precursor vapor contained in the heated metalorganic precursor line upstream of the central injector column to a temperature range between about 70 degrees Centigrade and 200 degrees Centigrade and a processor circuit can be operatively coupled to the heated metalorganic precursor line and configured to maintain a temperature of the low vapor pressure metalorganic precursor vapor within the temperature range.