Deposition

Deposition is any process that grows, coats, or otherwise transfers a material onto the substrate.

Technologies

Typical technologies include atomic layer deposition (ALD), chemical vapor deposition (CVD), electrodeposition/ electroplating or electrochemical deposition (ECD), and physical vapor deposition (PVD).

Atomic layer deposition (ALD)

Atomic Layer Deposition (ALD) at the LNF is performed on the Oxford OpAL ALD system that currently offers three films Alumina/Aluminum Oxide (Al₂O₃), Hafnia/Hafnium Oxide (HfO₂), and Zinc Oxide (ZnO).

Chemical vapor deposition (CVD)

Chemical vapor deposition (CVD) consists of the substrate being exposed to one or more volatile precursors, which react and/or decompose on the substrate surface to produce the desired deposit. There are many methods for enhancing the chemical reaction rates of the precursors. The LNF has fourteen Low Pressure CVD (LPCVD) furnace tubes and five Plasma Enhanced CVD (PECVD) chambers.

Electrodeposition/ Electroplating/ Electrochemical deposition (ECD)

Electrodeposition, which is available at LNF for Au, Cu, Ni, In, and NiFe; is the technique recommended when metal layers of more than a micron of thickness are needed. The principle is simple: positive ions are attracted to the negative electrode (anode which is the sample in the case of metal deposition) and negative ions travel towards the cathode or positive electrode. ECD is an electrochemical cell, which consists of a cathode, anode, and electrolyte that contains the ion to be deposited.

Physical vapor deposition (PVD)

Physical vapor deposition (PVD) describes a variety of vacuum deposition methods used to deposit thin films by the condensation of a vaporized form of the desired film material onto various substrates.

Figures of merit

Deposition rate

The amount of material deposited in units of time, typically expressed in angstroms per second or minute.

Refractive index

Defines optical properties of a given material for a specific frequency or wavelength of light. Also known as index of refraction n.

Film Stress

The elastic mismatch between the thin film deposited and the substrate that results in a change in substrate curvature. Residual stress is typically defined by a unit of measurement (MPa) across a given area.