Seminar information:
Plasma-Based Technology in Microelectronics, Nanotechnology, and Biomedical Science
Paul K Chu Department of Physics & Materials Science, City University of Hong Kong
Seminar time: May 29 (Thursday) 10:00-11:00
Seminar place: 205 classroom, School of Materials Science and Engineering
1. Abstract
Plasma-based ion implantation and deposition are useful techniques in many applications. In addition to the ability to modify materials surfaces, novel structures can be fabricated. Another advantage is that the surface characteristics such as mechanical properties and biocompatibility can be selectively enhanced with the favorable bulk attributes of the materials unchanged. In this seminar, recent research works conducted in our laboratory pertaining to microelectronics and biomedical engineering will be described. Silicon-on-insulator (SOI) is expected to replace conventional bulk silicon substrates in many microelectronic devices because it possesses advantages such as the reduction of parasitic capacitance, excellent sub-threshold slope, elimination of latch up, and resistance to radiation. By using hydrogen plasma immersion ion implantation in conjunction with layer transfer technology, we have produced the first 100mm and 150mm full SOI wafers using plasma technology. As device dimensions continue to shrink, wider applications of SOI in microelectronics are hampered by the self-heating effects caused by the poor thermal conductivity of the buried silicon dioxide layer. We have produced alternative buried insulators such as diamond-like carbon that possess better thermal conductivity compared to conventional silicon dioxide using plasma immersion ion implantation and deposition (PIII&D) and successfully fabricated SOI structures with improved thermal stability. The use of low-energy plasma hydrogenation to substitute for costly beam-line hydrogen ion implantation in the ion-cutting layer transfer technology will also be discussed.
In biomedical engineering, plasma spraying is a versatile technique to produce relatively thick ceramic coatings on orthopedic implant surfaces. We have discovered that plasma-sprayed nanostructured TiO2 coatings favor the growth of apatite. The surface bioactivity is enhanced by hydrogen plasma implantation. The results and mechanism will be discussed. Our recent work on the improvement of surface antibacterial properties of biomaterials and blood compatibility of cardiovascular materials as well as development of plasma-treated smart spinal deformity correction medical implants will be described.
2. About the speaker
Paul K Chu is Professor (Chair) of Materials Engineering in the Department of Physics and Materials Science in City University of Hong Kong. He received his BS in mathematics from The Ohio State University and MS and PhD in chemistry from Cornell University. His research activities are quite diverse, spanning plasma science and engineering and many types of materials including microelectronic, optoelectronic, biomedical, and functional materials. Paul is co-editor of 3 books and has written 20 book chapters and more than 600 journal papers, including 6 papers in journals with impact factors over 10, more than 200 papers in journals with impact factors over 2, and specifically more than 100 papers in Applied Physics Letters / Journal of Applied Physics. He has given 600 presentations in international conferences, more than 50 of which are plenary, keynote, or invited. He is credited by ISI Thomson Scientific as one of the top 0.1% scientists in materials science and 0.5% in engineering and all fields internationally. He is senior editor of IEEE Transactions on Plasma Science, associate editor of International Journal of Plasma Science and Engineering and Materials Science and Engineering Reports, and a member of the editorial board of Surface and Interface Analysis, International Journal of Molecular Engineering, and Recent Patents on Materials Science. He has co-edited 4 special issues in Surface and Coatings Technology and IEEE Transactions on Plasma Science and 1 Materials Research Society (MRS) conference proceedings. He is a member of the IEEE Plasma Science and Applications Executive Committee, Plasma-Based Ion Implantation and Deposition Executive Committee, and Ion Implantation Technology Executive Committee and symposium organizer of MRS Spring Meetings in San Francisco. He holds concurrent professorship in 10 universities and research institutes in China, including Peking University, Nanjing University, Fudan University, and Shanghai Institute of Ceramics. Paul has been awarded 8 US and 5 Chinese patents, which have been cited more than 50 times by IBM, Samsung, LSI Logic, Applied Materials, and so on in their patent applications. Paul has founded 3 companies and is Fellow of the American Vacuum Society (AVS), Institute of Electrical and Electronic Engineering (IEEE), and HKIE (Hong Kong Institution of Engineers - materials division as well as biomedical engineering division). He has won many awards, including the 2007 IEEE Nuclear and Plasma Sciences Society Merit Award which is the most prestigious honor given by IEEE in the areas of nuclear and plasma sciences.