The team has developed a new thin-film deposition technology for high-performance materials that is low energy, scalable, and potentially low cost. They recently reported via publication the formation of complex oxide perovskites in single crystalline hetero-epitaxial form and also specifically BiFeO3 in phase-pure polycrystalline form on SiO2/Si. This is important because the new technology enables production of a simple perovskite Pb-free single-crystal functional complex oxide films with crystalline quality, nanoscale control, and physical properties comparable to those obtained using much more expensive tools and processes. This technology could also be highly enabling in that it utilizes atomic layer deposition, thereby permitting conformal growth on high surface area per unit volume structures, and therefore a three- dimensional architecture may be realized. Replacement of Pb with Bi in these film structures gives a ferroelectric polarization with a larger charge per unit area, potentially enabling enhancements in device performance (e.g. non-volatile memory, wireless communications, and capacitors for energy storage).
Scaling and the roadmap is currently limited by MOCVD (and ALD) using lead zirconate titanate (PZT) because of inhomogeneities in Zr and Ti that result in nanoscale conformally-coated 3D structures that result in unacceptable variations in properties/performance. Thus, a process that uses a simple perovskite material would address this issue, particularly if it can outperform PZT. The customer need also relates to a technology that can deliver reduction in the use and waste disposal of Pb and Pb-based precursors, reduction in manufacturing cost through innovations in thin film deposition and process technology to reduce precursor waste, and an opportunity to increase the performance of existing technologies through a replacement material that has higher FE polarization (and therefore induced charge) and a process technology that is truly compatible with finer 3D nanoscale architectures to support scaling to future nodes.
