| AVS 65th International Symposium & Exhibition | |
| Thin Films Division | Thursday Sessions |
| Session TF+PS-ThM |
| Session: | Deposition Processes for 3D and Extreme Geometries |
| Presenter: | Dhruv Shah, Brigham Young University |
| Authors: | D.S. Shah, Brigham Young University D.I. Patel, Brigham Young University D.J. Jacobsen, Brigham Young University J.E. Erickson, Brigham Young University M.R. Linford, Brigham Young University |
| Correspondent: | Click to Email |
Atomic layer deposition (ALD) involves layer-by-layer deposition due to sequential exposure of two precursors to as substrate . ALD was developed in the late 1970s by Suntola and co-workers as a modification of chemical vapor deposition (CVD). In ALD, the dosing and purging steps are separated to ensure that each precursor saturates the surface before the other precursor enters the chemical reactor. ALD is widely used in the semiconductor and microelectronics industry to deposit thin films of various oxides on different substrates. ALD can be operated in two modes: plasma assisted and thermally assisted. Thermally assisted ALD has been widely used due to its high uniformity and conformality in depositing thin films on a variety of substrates.
Here we report alumina deposition by ALD using trimethylaluminum and water as precursors on silicon substrates. We optimized the process on flat surfaces like silicon shards, and extrapolate the process to high aspect ratio devices and powders, ultimately confirming the deposition on these high aspect ratio materials. Achieving high degrees of consistency and uniformity for deposition on powders through a frit using ALD has been difficult. We tried multiple recipes for alumina deposition, optimizing the dose time, purge time and effective exposure of the precursor on the substrate to achieve uniform results. Our thin films are characterized by spectroscopic ellipsometry (SE), water contact angle goniometry, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and/or transmission electron microscopy (TEM). The thin films we have obtained on planar substrates using ALD vary in thickness from 0.5 – 41.0 nm. These thin films were used to conduct a multiple sample analysis (MSA) in SE to obtain the optical constants of alumina. Since alumina is one of the most commonly used material in microfabrication, its optical constants will be useful in the field.