 Tile-Target Sputtering Process for Sub-50nm Ferroelectric Sc0.28Al0.78N Films Sushant Rassay and Faysal Hakim Authors: Sushant Rassay, Faysal Hakim, Roozbeh Tabrizian Faculty Mentor: Roozbeh Tabrizian, PhD College: College of Engineering Department: Electrical and Computer Engineering |
|
AbstractThe demonstration of ferroelectricity in scandium-aluminum nitride films (ScxAl1-xN) has initiated an exploratory barrage across multi-disciplinary areas such as memory devices, MEMS sensors and energy harvesters, and RF acoustic devices. In the recent past, various reports on ferroelectricity in much thicker ScAlN films showing very large coercive fields (Ec) have accelerated the need for thickness scaling to enable the use of ferroelectric polarization switching within limited available voltages on the chip. Here, we report an optimized reactive magnetron sputtering process enabling highly crystalline growth of ferroelectric Sc0.28Al0.72N films with thicknesses scaled down to 25nm. Unlike conventional dual-target approaches that use separate Sc and Al targets, in our approach a single segmented Sc-Al target created from configurable Sc and Al tiles is used. This approach not only reduces the complexity of the sputtering system, but also significantly improves the uniformity of film properties across the wafer and enables highly effective stress adjustment towards tensile films. In this process, the Sc concentration is controlled over 22 to 32 atomic percent through optimizing N2/Ar relative flow rate and without the need for physical configuration of the target.Sc0.28Al0.72N films with thicknesses over 25nm to 200nm are sputtered on 150mm Si wafers.
|
|
Poster
|
|
