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thin films research lab @ caltech
The research
in this lab is mainly concerned with the growth of thin films by Chemical
Vapor Deposition (CVD). CVD is a crucial step in the manufacturing
of integrated circuits, semiconductor lasers, micro-electro-mechanical systems
(MEMS) and many other devices. Research in this area is interdisciplinary.
drawing on the fields of heat transfer, fluid dynamics, control, chemistry
and materials science, among others.
Currently, our research focuses on developing intelligent CVD techniques for the synthesis of ferroelectric materials as part of a project labeled: Engineering Microstructural Complexity in Ferroelectric Devices . The project is supported through a Department of Defense Multidisciplinary University Research Initiative (MURI) and administered by the Army Research Office. The porject's goal is to develop miniaturized ferroelectric devices (micro-pumps and arrays of actuators on chips) as a test-bed for a new approach that integrates comprehensive materials modeling, theory, simulation, processing, characterization as well as design and fabrication. Such an integrated approach to manipulating materials is becoming all the more necessary to build the next generation of micro and nano scale devices. In order to integrate highly textured ferroelectric thin films with silicon, we are currently investigating deposition onto templates created using Ion Bean Assisted Deposition (IBAD).
In the context of this approach, in-situ techniques are of particular interest to us from a fundamental standpoint, as they lay the foundation for an intelligent approach to film synthesis. Two in-situ characterization techniques are currently employed in the lab: Fourier Transform Infrared Spectrometry (FTIR) and Coherent Gradient Sensing (CGS).
The lab employs state of the art equipment including a custom built CVD reactor (top left) that has the uniue advantage of full (angled and glancing) optical access to carry out in-situ characterization. CGS interferograms (example top right) monitor curvature changes and subsequentlly mechanical stresses furing film evolution. FTIR provides us with direct spectroscopic data that can be calibrated against chemical composition, crystal orientation, temperature, etc.. We are continuosuly improving and developing new in-situ techniques. Other useful ex-situ characterization techniques, we are directly involved with, include Rutherford Backscattering Spectrometry (RBS) and X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).
Previous reserach has focused on various aspects of the synthesis of YBCO super-conducting thin films, namely multiscale process simulations and spectroscopic characterization.
Currently, our research focuses on developing intelligent CVD techniques for the synthesis of ferroelectric materials as part of a project labeled: Engineering Microstructural Complexity in Ferroelectric Devices . The project is supported through a Department of Defense Multidisciplinary University Research Initiative (MURI) and administered by the Army Research Office. The porject's goal is to develop miniaturized ferroelectric devices (micro-pumps and arrays of actuators on chips) as a test-bed for a new approach that integrates comprehensive materials modeling, theory, simulation, processing, characterization as well as design and fabrication. Such an integrated approach to manipulating materials is becoming all the more necessary to build the next generation of micro and nano scale devices. In order to integrate highly textured ferroelectric thin films with silicon, we are currently investigating deposition onto templates created using Ion Bean Assisted Deposition (IBAD).
In the context of this approach, in-situ techniques are of particular interest to us from a fundamental standpoint, as they lay the foundation for an intelligent approach to film synthesis. Two in-situ characterization techniques are currently employed in the lab: Fourier Transform Infrared Spectrometry (FTIR) and Coherent Gradient Sensing (CGS).
The lab employs state of the art equipment including a custom built CVD reactor (top left) that has the uniue advantage of full (angled and glancing) optical access to carry out in-situ characterization. CGS interferograms (example top right) monitor curvature changes and subsequentlly mechanical stresses furing film evolution. FTIR provides us with direct spectroscopic data that can be calibrated against chemical composition, crystal orientation, temperature, etc.. We are continuosuly improving and developing new in-situ techniques. Other useful ex-situ characterization techniques, we are directly involved with, include Rutherford Backscattering Spectrometry (RBS) and X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).
Previous reserach has focused on various aspects of the synthesis of YBCO super-conducting thin films, namely multiscale process simulations and spectroscopic characterization.
Thin film deposition involves length and time scales varying by orders of magnitude, from the atomic scales that govern important processes like surface adsorption, diffusion, and reaction, to the macroscopic reactor scales. Often, the quality of the film is determined by microscale features (microstructure, step coverage, etc.) but sensing and actuation can usually only be done at the reactor scale. This presents a considerable challenge to high quality film synthesis