THESIS
2007
ix, 82 leaves : ill. ; 30 cm
Abstract
The successful integration of semiconductor technology and biological DNA detection process has always been the major objective of bio-sensor designers. The advance in integrated circuit (IC) fabrication technology not only allows smaller, cheaper and faster bio-sensors to be made, the idea of “lab-on-chip” can also be realized in the near future. In this thesis, the design issues of silicon-based sensing devices for enhanced DNA detection are studied and discussed....[
Read more ]
The successful integration of semiconductor technology and biological DNA detection process has always been the major objective of bio-sensor designers. The advance in integrated circuit (IC) fabrication technology not only allows smaller, cheaper and faster bio-sensors to be made, the idea of “lab-on-chip” can also be realized in the near future. In this thesis, the design issues of silicon-based sensing devices for enhanced DNA detection are studied and discussed.
First, the label-free detection is realized by a MOSFET-based sensor. With the device fabricated in NFF, experiments are performed to detect the intrinsic charge of DNA molecules. Experimental result demonstrates the availability of this kind of device, and the problem of the detection limitation is presented with optimization considerations.
Secondly, an investigation on the characteristics of different bio-interfaces is performed to improve the probe DNA density. Several CMOS-compatible materials are modified and tested as the substrate layer for DNA probe immobilization. Oxygen plasma is introduced as a clean, convenient surface modification tool with an optimized treatment time. The surface properties as the hydrophobicity and the capacity to capture DNA probes are examined by contact angle measurement and fluorescent labeling detection experiments.
Thirdly, one technique called “micro-concentration” is developed to improve the detection sensitivity, i.e. to detect DNA with a lower concentration. After the fluorocarbon (FC) film coating and lithography, the detectable DNA concentration can be extended down to 1% of the original detection limitation. The successful experimental demonstration of this technique indicates some future implementation to the silicon-based DNA sensors.
Finally, the effect of device scaling is studied based on photodiode detection platform. The process illustration of gold nano-particle labeling and silver enhancement is presented in the 2D dimension. From the results, it is known that device scaling has a positive impact on the detection sensitivity with a detailed explanation of the “edge effect”. Also, issue of background noise reduction is considered for further optimization.
Post a Comment