US 2024/0071759 A1 · Confined Growth of 2D Materials and Their Heterostructures

Abstract

Two-dimensional (2D) materials and their heterostructures show a promising path for next generation electronics. Nevertheless, there are challenges with (i) controlling monolayer (ML)-by-ML 2D material growth, (ii) maintaining single-domain growth, and (iii) controlling the number of layers and crystallinity at the wafer-scale. The deterministic confined growth techniques disclosed here address these challenges simultaneously to produce wafer-scale single-domain 2D MLs and their heterostructures on arbitrary substrates. The growth of the first nuclei is confined by patterning SiO2 masks on 2-inch substrates to define selective or confined growth areas. Each growth area or trench is just a few microns wide and is filled with a single-domain ML before the second set of nuclei is introduced. Growing the second set of nuclei within the trenches yields an array of single-domain bilayers at the 2-inch wafer scale. Devices made with the single-domain bilayers exhibit excellent performance over the entire wafer.

Claims28

Dependent claims

A method comprising the steps of:

(a) providing a substrate of a first material;
(b) depositing a mask material on the substrate;
(c) forming a trench array on the mask material, the trench array comprising a plurality of trenches, each trench having a trench geometry having lateral dimensions of l×w, where each of l and w is picked to have a maximum dimension of 2 μm and each trench having an exposed portion of the substrate surrounded by sidewalls formed of the mask material;
(d) depositing an adatom of a second material on the exposed portion of the substrate, wherein a first binding energy between the first material and the second material is greater than a second binding energy between the mask material and the second material;
(e) allowing the adatom to selectively nucleate into a nucleus within each trench in the trench array;
and
(f) growing the nucleus within each trench in the trench array;
and
wherein the lateral dimensions associated with the trench geometry limit growth of the nucleus to a single-domain monolayer of the second material.

6 more elements

A method comprising the steps of:

(a) providing a substrate of a first material, the first material having a first Gibbs free energy;
(b) depositing a mask material on the substrate, the mask material having a second Gibbs free energy, the second Gibbs free energy higher than the first Gibbs free energy;
(c) forming a trench array on the mask material, the trench array comprising a plurality of trenches, each trench having a trench geometry having lateral dimensions of l×w, where each of l and w is picked to have a maximum dimension of 2 μm and each trench having an exposed portion of the substrate surrounded by sidewalls formed of the mask material;
(d) depositing an adatom of a second material on the exposed portion of the substrate;
(e) allowing the adatom to selectively nucleate into a first nucleus within each trench in the trench array;
(f) growing the first nucleus within each trench in the trench array, wherein the lateral dimensions associated with the trench geometry limit growth of the first nucleus to a first single-domain monolayer of the second material;
(g) waiting for an incubation period;
(h) depositing another adatom of a third material on top of the first single-domain monolayer of at least one trench in the trench array;
(i) allowing the another adatom of the third material to selectively nucleate into a second nucleus on top of the first single-domain monolayer within the at least one trench in the trench array;
and
(j) growing the nucleus within the at least one trench in the trench array;
wherein the lateral dimensions associated with the trench geometry limit growth of the second nucleus to a second single-domain monolayer of the third material, and
wherein the first single-domain monolayer and the second single-domain monolayer form a bilayer.

10 more elements

Dependencies are inferred from the claim text.

Confined Growth of 2D Materials and Their Heterostructures

Life of this patent

Confined Growth of 2D Materials and Their Heterostructures

Life of this patent

Abstract

Claims28