"Creative Epitaxy: Finding Ways to Violate Assumptions that Breach Material Barriers"
Prof. W. Alan Doolittle, School of Electrical and Computer Engineering, Georgia Institute of Technology
Tuesday, January 11, 2022
12:00-1:00 PM EST
Abstract: Epitaxial processes are considered routine for applications spanning established industries from the silicon and GaN semiconductor industries to cutting edge research. As many as 10,000 epitaxial reactors crank out billions of dollars’ worth of light emitting diode chips for solid state white lighting alone. Those metrics increase 100-fold for silicon applications. Epitaxy is core to countless industries but is mostly performed in ways that have not changed for decades. But epitaxy can also be performed in non-standard ways to overcome “perceived” barriers to materials synthesis. Several examples will be given in this talk including: 1) Dynamic control of surface chemistry so as to enable higher solubility of desirable impurities; 2) Dynamic control of surface energy facilitating 3D control of alloy composition and material properties; 3) Electrothermal control of epitaxy to enable metastable phase materials; and 4) the “invention” of the widest semiconductor known. Each of these example problems has been solved by a common “thought process” wherein the fundamental assumption behind the limitation was defined and ways of violating the identified assumption was explored leading to new functionality in materials. The importance of the process - assumption identification and violation - will be discussed in hopes of conveying an important approach to solving hard problems. New emerging industries such as optoelectronics, neuromorphic computing and power electronics will be highlighted as beneficiaries of these unique approaches.
Bio: Dr. W. Alan Doolittle is the Joseph M. Pettit professor in the School of Electrical and Computer Engineering at Georgia Institute of Technology. Doolittle is a proud, two-time Georgia Tech alumnus, earning his B.E.E. degree with highest honors in 1989 and his Ph.D. in Electrical Engineering in 1996. Doolittle leads the Advanced Semiconductor Technology Facility with an estimated equipment capitalization of $8 million and works in the areas of microelectronic fabrication, materials growth, materials and device characterization, neuromorphic computational devices, power devices, high frequency transistors and optoelectronic devices. Doolittle pioneered the area of hyper doping of wide bandgap semiconductors which has enabled the creation of new semiconductors including the widest bandgap semiconductor known, new devices that utilize quantum mechanical processes to reduce power losses and to allow new ways of interconnecting advanced power and optoelectronic devices. Doolittle has also pioneered the synthesis of lithium-metal-oxides which have recently gained attraction for very low power neuromorphic devices- devices that emulate human brain functionality.