WG2 Growth Control

Workgroup Leader: Gertjan Koster 

WG2 Growth Control (GC) is in charge of pursuing the first TECHNOLOGY Objective “To foster the development of a technology for the growth of in-situ-quality-controlled, large-area epitaxial oxide films and heterostructures on different substrates including Si”. WG2 will act in synergy with the Management WG for the organization of technical meetings and roundtables and to join contacts with private corporations, also for the presentation of joint applications. In synergy with the Management WG and with WG3 it will publish a volume that is intended to serve as a technological roadmap for transition-oxide-based electronics. The specific scientific activities fostered within this WG are described by three tasks.

WG2-T1 “Large area growth”

Task Leader: Judith Driscoll (University of Cambridge, UK)

High throuput, large area growth of oxide thin films is today a largely unsolved problem which needs to be addressed. The technique that proved to be by far the most successful in oxide film growth, i.e. pulsed laser deposition, has is generally considered unsuitable to large area deposition, due to the limited dimension of the plume and to the reduced deposition rate. Typical large area deposition techniques employed in industry, as chemical vapour deposition, have not achieved so far the very high level of crystalline quality that is needed for TMO samples. Nevertheless the joint use of high power excimer lasers, laser beam rastering on target and sample movement during growth appears as a promising solution allowing to rescale the highly successful PLD growth from laboratory to industrial level. The task “Large area growth” will coordinate the groups acting within the TO-BE Action on this topic.

WG2-T2 “Perovskite-on-Si”.

Task Leader: Florencio Sanchez (ICMAB, ES)

Oxide thin films and heterostructures of peroskite-related materials are deposited often in research laboratories on single crystal oxide substrates, such as SrTiO 3 . The use of such substrates is not cost effective, not compatible with industrial manufacturing techniques and therefore does not allow the direct integration of oxide-based films with conventional technologies. High quality epitaxial growth of complex oxides on silicon or on other microelectronic substrates (as Al 2 O 3 sapphire) is needed. The growth of very high quality epitaxial SrTiO 3 films on Si has been recently demonstrated, mostly by molecular beam epitaxy. Rescaling such technology to an industrial level would make commercially available high quality “Perovskite-on-Si” (or “Perovskite-on-sapphire”) substrate, replicating the well established SOI (silicon on insulator) or SOS (silicon on sapphire) technologies, to be used both in research and in industry applications. The task “Perovskite-on-Si” will ensure that this topic will be coordinated between the groups acting within the TO-BE Action.

WG2-T3 “Real-time monitoring”

Task Leader: Alexei Kalaboukhov (Chalmers University, SE)

Transition metal oxides are highly sensitive to small amounts of crystallographic defects and completely lose their electronic properties when crystal order is lost. TMO-based technologies require therefore an unprecedented degree of control of the growth process to guarantee that the complex crystal structure is reproduced in thin film form with the highest degree of perfection. This task will coordinate a team of laboratories interested in increasing the real time control of thin film growth. One of the tasks of this group will be analysing novel techniques that can be applied in the specific growth conditions of oxides. This includes modified RHEED concepts, fast imaging and spectroscopy of the laser plume, surface second harmonic generation, 2D Curvature and Stress Monitoring, real time AFM, real time X-ray diffraction. Furthermore, typical surface science techniques that require UHV and might not be compatible with the TMO growth conditions (as LEED, XPS) will be applied through direct UHV transfer of the sample from the deposition chamber.