Preparation of Dielectric Thin-Film Libraries by Sol–Gel Techniques
The short innovation cycles in communication technology require the development and optimization of high-performance dielectrics for passive integration and miniaturization, utilized, for example, in bandpass filters, antennas, or amplifiers. Conventional one-at-a-time techniques for developing materials are slow and expensive. Thus acceleration of the search by high-throughput technologies is attractive. High-throughput experimentation (HTE) enables a rapid exploration of multidimensional composition and processing spaces and is on the way to becoming an efficient tool for materials discovery and optimization. It has been successfully applied to homogeneous and heterogeneous catalysis1 as well as to a broad range of materials. The HTE process is composed of design of experiment,2 library synthesis, and property analysis.3 In the field of catalysis, synthesis techniques for powder or thick films have mainly adopted variations of wet chemical processes, transferred to pipetting robots or ink-jet dispensers,1 while in the search for electronic materials gas-phase routes for thin films such as physical or chemical vapor deposition in combination with masking or gradient techniques are commonly applied.4 Due to its complexity the conventional
way of preparation of dielectric materials as ceramics does not lend itself to high-throughput experimentation. Wet synthesis techniques in analogy to the catalysis work, however, seemed more attractive, because it is a low-cost technique and principally allows to broadly vary composition at extremely mild synthesis conditions. However, HTE sol-gel techniques for producing arrays of defined thin films of identical thickness (< 2 µm) on libraries are not known, especially not for the elemental combinations of interest for dielectric applications.