Increasing accessibility of 3D printing in traditional educational settings has allowed for unique pedagogical opportunities. The on-demand production of inexpensive and customizable laboratory components provides students hands-on experience with equipment that could otherwise be prohibitively expensive. Many “open education” communities are collaborating to publish freely shareable and modifiable designs for instrumentation and componentry that supplements learning and experimental research. In the interest of contributing to this movement, an ellipsometer is designed and constructed using readily available and inexpensive componentry along with 3D printable opto-mechanics. A modeling system in Microsoft Excel is also created to fit sample properties to instrument output.<br/><br/>Ellipsometry is an optical analysis technique whereby light reflected from a sample surface experiences a change in polarization state due to phase delay and anisotropic reflection. This phenomenon enables one to produce non-destructive measurements of film thickness, index of refraction, surface roughness, and other optical constants. Ellipsometric techniques are particularly convenient for characterizing films and coatings in the semiconductor or optics industries.<br/><br/>The 3D printed ellipsometer was used to determine tetraethyl orthosilicate (TEOS) film thickness across five silicon wafer substrates. Photometric measurements made through a range of angles of incidence are fit to a model in Microsoft Excel using regression analysis. The efficacy of the instrument was determined by comparison of sample film thickness as measured by the industrially available MProbe20 Vis reflectometer from SemiconSoft. Good fitment of ellipsometer data to model yielded an average film thickness difference of 0.77% between instruments. All but one of the sample film thicknesses were determined to be significantly different to 95% by t-test, possibly owing to systematic differences between the reflectometry and ellipsometry techniques, including their handling of sample surface inhomogeneity.

Optical measurements on a budget: A 3D printed ellipsometer

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.