Deposition and Characterization of Electronics Materials in Bionanotechnology and Micro/Nano-electronics
thesisposted on 01.08.2019, 00:00 by Nickolas Dean Anderson
Microelectronic materials and especially electronics material for flexible electronics are of increasing interest in numerous applications from wearable health monitoring, displays, and consumer electronics to structural health monitoring and energy harvesting. Deposition of materials with the desired thickness and composition through scalable processes is vital to ensure flexibility, device functionality and translation to commercial processes. Of particular interest are graphic printing techniques and atomic layer deposition (ALD). Graphic printing techniques are of interest for large-scale fabrication where low cost is the primary driving force, thick films are desirable and constraints on device performance are relatively relaxed. ALD is used for large-scale fabrication when highly conformal, nm-thick films are required for device performance and reliability. In this thesis, screen printing, a graphic printing modality, was used to fabricate devices for large-area, low-cost structural monitoring applications. Such applications include the structural monitoring of aircraft, where a quantitative measurement system can greatly improve the current maintenance programs that primarily rely on qualitative information. Different process parameters and unique ink formulations were investigated in order to enhance the sensitivity of strain gauges and improve performance of strain sensor arrays. The performance of the gauges and auxiliary circuit materials were characterized in terms of reproducibility of strain sensitivity, reliability of dielectrics and conductors, fatigue and temperature responses as well as their microstructure. In addition, ALD was used for the first time to conformally coat collagen films with platinum for biosensor applications. The platinum coated collagen was characterized based on its resistivity, flexibility, morphology, and surface chemistry. Lastly, selective ALD of zirconia on silicon compared to copper substrates was improved by a unique pre-deposition treatment of the substrates, where improved selectivity is critical for future electronics fabrication. The selective ALD process for zirconia was studied in terms of different copper substrates, differences in the chemical species present on the substrates and the effect of different ALD process changes, all of which led to plausible mechanisms for the area selective ALD process.