| AVS 56th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology | Wednesday Sessions |
| Session NS-WeM |
| Session: | Nanoscale Devices and Sensors and Welch Award |
| Presenter: | W. Hu, University of Texas at Dallas |
| Authors: | S. Regonda, University of Texas at Dallas K. Trivedi, University of Texas at Dallas P. Fernandes, University of Texas at Dallas R. Tian, University of Texas at Dallas O. Seitz, University of Texas at Dallas J. Gao, University of Texas at Dallas E.M. Vogel, University of Texas at Dallas Y. Chabal, University of Texas at Dallas W. Hu, University of Texas at Dallas |
| Correspondent: | Click to Email |
Among the emerging devices for the future technology in the nanoscale regime, silicon nanowire (SiNW) devices have received significant attention for applications in logic gates, interconnects, photo detectors and biological and chemical sensors. For biosensing, femtomolar (fM) level detection of protein in solution has been demonstrated using both chemically synthesized nanowires [1] and lithographically defined nanowire field effect transistors (FETs) [2]. This type of sensor offers ultrasensitivity, rapid electronic readout, and does not require bulky sensing apparatus. It has a strong potential to be an ultra-portable and low cost biosensing platform that is badly needed for disease diagnostics and early detection.
In this work, we present our recent work on the similar nanowire FETs defined by e-beam lithography and standard Si processing technologies. This approach provides excellent manufacturability and feasibility of integrating circuitry with the sensor array on a single chip for ultimate system miniaturation and low manufacturing cost. In our process, SiNWs are defined by e-beam lithography in hydrogen silses quioxane resist, followed by a new two-step Si etch process, which is designed to improve the process reliability and controllability. SiNW FETs of 30-100 nm in widths, 10-30 nm in thickness, 5-80 µm in length have been successfully fabricated on Si on insulator (SOI) substrates. Uniform devices with sub threshold slope (SS) of 80 mV/dec and On/off ratio greater than 107 have been made reproducibly. We will present various device design and fabrication considerations for using nanoelectronic FETs as biosensors, e.g. source/drain doping effects, oxidation effects, plasma treatment effects, buffer solution effects and stability. These device issues are quite different from conventional use of nanowires in logic gates. We further integrate these SiNW FETs with SU8 microfluidic channels to detect proteins at low abundance in solution. Preliminary results have indicated a sensitivity or detection limit of 2fM. We expect to present controlled sensing results of protein biomarker under controlled flow conditions.
[1] Patolsky, F., Zheng, G and Lieber, C.M, Nat.Protocols 1, 1711-1724 (2006)
[2] Eric Stern, et al. Nature 445, 519-522 (2007)