2D Indium Selenide MOCVD Growth for Wafer-Scale Phase Control

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Solution Overview

Problem

There is a need for large-area growth techniques to produce high-quality, polymorph-selective, and thickness-controlled two-dimensional indium selenide (InSe or In2Se3) thin films, which are essential for advanced electronics due to their superior electrostatic control and mobility, but existing methods have not achieved wafer-scale synthesis.

Innovation Solution

The method involves using vertical, cold-walled metal-organic chemical vapor deposition (MOCVD) with controlled flux ratios of In and Se sources, modulating the flow of precursors to achieve layer-by-layer growth on c-plane sapphire wafers, allowing for the selective growth of InSe or In2Se3 with tunable optical properties and electrical transport comparable to single-crystalline flakes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional deposition methods are used, then small-area or low-quality 2D InSe films can be produced, but wafer-scale high-quality polymorph-selective growth is not achieved

Engineering Contradiction:

Improvefilm quality and polymorph selectivityVSAvoidwafer scale production area

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The deposition process is segmented into distinct growth stages with controlled precursor delivery. The showerhead reactor divides the wafer surface into multiple deposition zones, allowing independent control of In and Se precursor flux across different radial positions. This segmentation enables precise control of growth conditions across the entire wafer surface, achieving uniform high-quality 2D InSe films from center to edge.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic adjustment of deposition parameters including temperature (300-500°C), precursor flow rates, and pressure during the growth process. By continuously monitoring and adjusting these parameters, the system maintains optimal conditions for polymorph-selective growth of InSe while scaling to wafer dimensions, achieving both high quality and large area production.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If flux ratio of Se/In is not controlled, then stoichiometry and polymorph formation are unpredictable, but with controlled flux ratio, phase-pure InSe or In2Se3 can be selectively grown

Engineering Contradiction:

Improvestoichiometry control and phase purityVSAvoidprecursor flow control system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system incorporates real-time monitoring of precursor flux and deposition rate, with feedback control mechanisms that adjust In and Se precursor delivery based on observed growth conditions. This feedback enables precise stoichiometry control and polymorph selection by maintaining optimal Se/In flux ratios throughout the deposition process, achieving phase-pure InSe or In2Se3 films.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The precursor delivery system dynamically adjusts flow rates of In and Se precursors during the deposition process. The showerhead reactor enables independent modulation of precursor flux at different radial positions and over time, allowing the system to adapt to changing growth conditions and maintain precise stoichiometry control for selective polymorph formation.

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If layer-by-layer growth is not achieved, then thickness control is poor, but with layer-by-layer growth, thickness can be precisely controlled

Engineering Contradiction:

Improvethickness controlVSAvoidgrowth time and deposition rate

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The deposition process employs periodic pulsing of precursor delivery to achieve layer-by-layer growth. By delivering precursors in controlled pulses rather than continuously, the system builds atomic layers sequentially with precise thickness control. This periodic action enables accurate thickness regulation while maintaining reasonable deposition rates through optimized pulse duration and frequency.

Inventive Principle:

Principle #19Periodic 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 approach enables the production of phase-pure, high-quality InSe or In2Se3 films on a wafer scale, suitable for back-end-of-line integration in logic transistors, with field-effect mobilities comparable to single-crystalline flakes and high on-to-off current ratios, facilitating their use in memory and logic devices.

Implementation Method 1

depositing on a substrate at least one layer of InSe or In2Se3 by MOCVD

Methodology Applied

Scientific EffectChemical Vapor Deposition: Chemical Vapour Deposition

Implementation Method 2

controlling the thickness of the 2D InSe or In2Se3 layers using layer-by-layer growth

Methodology Applied

Scientific EffectEpitaxy: Epitaxy

Data Source

PatentUS20250389052A1Novel synthesis of two-dimensional indium selenide

Publication Date: 2025.12.25 THE TRUSTEES OF THE UNIV OF PENNSYLVANIA

AI summary

Described herein is two-dimensional (2D) indium selenide (InSe or In2Se3) with a combination of favorable attributes. Also described herein are methods of making and using the 2D InSe or In2Se3.