1	Systematic Synthesis of Nano-Informatics Chips by Nano-Robotic Manipulation LI Wen Jung （李文荣） Centre for Micro and Nano Systems/ Shun Hing Institute of Advanced Engineering The Chinese University of Hong Kong
2	Project Description Almost 50 years have passed since J. Kilby and R. Noyce co-invented the Integrated Circuit (IC) technology in the winter of 1958. Without a doubt, the silicon-based IC technology has revolutionized many aspects of modern-day human life, including communications, computing, and entertainment. And, more recently, MEMS technology and advanced DNA-detection chips, both of which are derivatives of IC technology, are transforming methods that scientists and engineers used to perform physical sensing and opening up new frontiers in biotechnology, respectively. Some scientists and industrialists are concerned, however, that the well-recognized Moore’s Law, which states that the number of transistors that the IC industry can place in commercial chips will double every 2 to 3 years, is rapidly reaching a limit. That is, within a decade, it may take 4 to 6 years before the number of transistors can double in a chip. There are two fundamental limits which the IC industry is facing now: 1) the smallest feature ‘printable’ on a chip has reached both the optical-wavelength limit and electron-beam lithography limit, and 2) the thin films deposited on the chips are reaching atomic layer thickness limit. Hence, most experts predict that a new technology has to be developed, perhaps completely different from the lithography and silicon based IC technology, to ensure the future advancement of faster and low-power-consuming micro computing processors. Carbon Nanotubes (CNTs), since its discovery by Iijima in 1991, has become a major candidate that is considered as a promising replacement for silicon-based electronic elements. CNTs (or nanowires in general) have been experimentally determined to have many more desirable characteristics than silicon -- such as higher yield-strength, higher thermal conductivity, and can be semi-conductive. Best of all, nanowires and CNTs can be made to have diameters of 1 to 10nm, which is at least an order of magnitude smaller than commercial IC transistors dimensions. This is the premise that IBM Zurich and Intel are both interested in developing computing chips based on CNT technology. However, due to the nano-scale dimensions of the CNTs, it is still very difficult to build and test circuit components and sensors consistently using CNTs as electronic or sensing elements. There are only 4 available techniques available today to construct CNT sensors: 1) onsite-catalytic growth (Stanford University and Samsung being the most successful groups, but controlling the conductive properties of CNTs is nearly impossible using this method), 2) SPM/AFM based nano-robotic manipulation (many groups are working on this, including the PI Prof. N. Xi’s group), 3) self-assembly based on chemical bonding (no working device has been demonstrated yet using this technique), and 4) dielectrophoretic (DEP) manipulation (Prof. Li’s group is the first in the world to demonstrate CNT sensor arrays made using DEP; his recent publication in Nanotechnology was cited by the Institute of Physics as one of the most downloaded articles in all of their published journals across many disciplines). In this project, we have formed an international research team to develop a systematic procedure to synthesize CNT and Nanowire based nano-electronic and nano-sensing chips. Within 3 years, we will produce a set of nano-chip synthesis rules that can be followed by researchers through out the world, thereby, establishing SHIAE at CUHK as one of the global leaders in engineering nano devices. Our team also includes few Co-Investigators who are technological leaders in sensor technologies and will perform detailed experimental characterization of the nano-chips built by CUHK. We will produce several types of physical-sensing chips that will revolutionize conventional sensing technologies spanning several technical disciplines. Some of the envisioned nano-informatics chips that will be built are: 1) low-power, high-spatial-resolution shear-stress sensors for aerodynamic measurements, 2) CNT-based electronic components and FPGAs, 3) CNT-based real-time bio-detection chips, 4) hybrid CNT-DNA-based electronic and sensing elements. The remaining sections of this document summarize our research plan, international collaboration scheme, project deliverables, and budget breakdown.
3	Project Team Project Coordinator: Prof. Wen J. Li, Centre for Micro and Nano Systems, The Chinese University of Hong Kong Prof. Ning XI’s group at the Robotics and Automation Laboratory at Michigan State University will focus on the AFM-based manipulations aspects of this project. Prof. Xi is a Co-I in this project. Prof. Tzung HSIAI’s group at the Dept. of Biomedical Engineering, University of Southern California, USA (He is a Co-I in this project. He would like to use the CNTs to detect shear-stress on heart cells has blood flows through an artery; he has performed the measurement using MEMS polysilicon sensors already. However, CNT sensors operate at much lower temperature and hence would not damage the heart cells) Prof. Steve TUNG’s group at the Dept. of Mechanical Engineering, University of Arkansas, USA (Prof. Tung is also a Co-I in this project. He will collaborate with our group on developing hybrid CNT-DNA-based sensors. His group has already demonstrated CNT-DNA self-assembled linkages recently. By combing his techniques with our manipulation technology, we aim to demonstrate macro-molecular sensors using CNT-DNA linked elements) Prof. K. W. Wong of Dept. of Physics, The Chinese University of Hong Kong, has also agreed to test our CNT-based chips for DNA and macro-molecular detection in their laboratory in Hong Kong.
4	Comparing CNT and Polysilicon sensors
5	AFM-Based Manipulation
6	Project Approach: DEP + Microrobotic Based Manipulation
7	Dielectrophoretic Manipulation (Wen J. LI)
8	Micro-Robotic Station for CNT Sensor Construction
9	Droplet Size: hydrophobicity and hydrophilicity considerations
10	From MEMS-CAD to CNT Sensors
11	Efficient micro-robotic spotting: Traveling Salesman Problem (TSP) Start at the upper-left corner After the calculation of 410 000 times (~4 days) Total cost: min = 60600, max = 85800 Total time required: min = 107 s, max = 122 s Time required for each sensor: min = 1.07 s, max = 1.22 s
12	MUMPs-CNT Sensor Chips: I-V Characteristic
13	Ultra-Low-Power Alcohol Vapor Sensors Based on Multi-Walled Carbon Nanotube
14	Experimental results for MWCNTs Sensors: Alcohol Vapor
15	Experimental Results for (COOH)-MWCNTs Sensors: Alcohol Vapors
16	Conference/Journal Publications King W. C. Lai, Carmen K. M. Fung and Wen J. Li, "Development of an Automated Microspotting System for Rapid Dielectrophoretic Fabrication of Bundled Carbon Nanotube Sensors," IEEE Transactions on Automation Science and Engineering (T-ASE) Special Issue on Nano-scale Automation and Assembly, accepted, to be published in July 2006. Mandy L. Y. Sin, Gary C. T. Chow, Carmen K. M. Fung, Wen J. Li, Philip Leong, K. W. Wong, and Terry Lee, “Ultra-Low-Power Alcohol Vapor Sensors Based on Multi-walled Carbon Nanotube”, 2006 IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS 2006), Zhuhai, China, Jan 18-21, 2006. Wenli Zhou, Gary Chow, Wen J. Li, Philip Leong, Carbon Nanotubes as Heating Elements for Micro-Bubble Generation, 2006 IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS 2006), Zhuhai, China, Jan 18-21, 2006. Mandy L. Y. Sin, Gary C. T. Chow, Carmen K. M. Fung, Wen J. Li, Philip Leong, K. W. Wong, and Terry Lee, “Chemically Functionalized Multi-Walled Carbon Nanotube Sensors for Ultra-Low-Power Alcohol Vapor Detection”, submitted, IEEE Int. Conf. on Nanotechnology, June 16-20, 2006, Cincinnati, USA.
17	Invited Presentations Wen J. Li, Special Invited Speaker, “Towards Fabrication of CNT-based Large-Scale-Integrated (LSI) Sensor Arrays”, The 2nd International Meeting on Microsensors and Microsystems, Tainan, Taiwan, 15-18 January 2006. (http://imu2.ncku.edu.tw/) Wen J. Li, Keynote Speaker, "Reversible and Ultra-Low-Power Alcohol Vapor Sensors based on Functionalized CNT Elements ", The 2nd International Symposium on Micro and Nano Technology, Hsinchu, Taiwan, March 29-31, 2006. (http://www.mems.nthu.edu.tw/ismnt-2/)
18	Project Research Fellows Ms. Mandy SIN, PhD Candidate, Automation and Computer-Aided Engineering Dept., CUHK – currently working on testing CNTs as flow sensors and chemical/biological sensors. Mr. Gary CT CHOW, MPhil Candidate, Computer Science and Engineering Dept., CUHK -- currently working on integrating CNTs onto 0.35um CMOS chip (supervised by project PI Prof. Philip Leong and co-supervised by Prof. Li). Mr. Patrick LEUNG, Summer Intern of SHIAE – worked for 1 month at SHIAE during winter break of 2006 on a project related to DEP manipulation of Au particles; currently at Cambridge to obtained his MPhil degree. Dr. King W. C. Lai, Postdoctoral Fellow of SHIAE – worked on automating the CNT spotting process to rapidly manufacture CNT-bases sensors. Has moved on to work for Prof. Ning Xi at Michigan State University as a postdoctoral fellow. We will continue to publish papers jointly and acknowledge the funding from SHIAE. Dr. Jennifer WL Zhou, Postdoctoral Fellow of SHIAE – worked on CNT bubble generators. Currently Associate Professor at Huazhong University of Science and Technology; will continue efforts in joint publications. Mr. Peng XIAO, MPhil Student, Automation and Computer-Aided Engineering Dept., CUHK – will enter ACAE Dept. in August 2006 to work on CNT thermal response modeling.
19	Summary Nano-Scale Sensing and Circuit Systems is the FUTURE -- A systematic fabrication process is becoming a reality Demonstrated an Automated Nano Sensor and Circuit Assembly Platform at CUHK