An integrated microfluidic device capable of performing a variety of genetic assays has been developed as a step towards building systems for widespread dissemination. The device integrates fluidic and thermal components such as heaters, temperature sensors, and addressable valves to control two nanoliter reactors in series followed by an electrophoretic separation. This combination of components is suitable for a variety of genetic analyses. As an example, we have successfully identified sequence-specific hemagglutinin A subtype for the A/LA/1/87 strain of influenza virus. The device uses a compact design and mass production technologies, making it an attractive platform for a variety of widely disseminated applications.

An active microvalve that uses a meltable piston in place of a conventional solid material to obstruct fluid flow in a microfluidic channel has been developed. This phase change valve is simple to operate and requires no additional fabrication steps. The valve is inherently latched, reusable, and leak-proof (to at least 250 psi) and can be electronically addressed using resistive heaters. The valve has been characterized for a range of operational parameters that will serve as a design guide. For the designs tested, piston displacements of 5 mm or more in 1 s have been achieved. Valves 1.4 mm in length in a 50 microm x 200 microm channel have been integrated on a biochemical reaction device, and successful DNA amplification using PCR has been achieved. The phase change valve can be easily implemented in an array format that can be used to realize complex microfluidic circuits.

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In this paper, we describe the design, construction and operation of two low cost thermal isolation techniques on a microfabricated DNA amplification and analysis device. The thermal conduit technique is based on a selective conduction mechanism, while the silicon back dicing technique is based on a selective insulation mechanism. The performances of the two techniques are compared both numerically and experimentally to that of the widely adopted but costly silicon back etching technique. Temperature gradients as high as 108 • C cm −1 , 92 • C cm −1 and 158 • C cm −1 can be achieved with the three techniques, respectively. Geometric optimization of the two low cost techniques is carried out to further improve their thermal performances. Combining those two techniques can provide comparable thermal isolation results as the back etching technique with significant cost reduction.

For the first time, embedded Si:C (eSi:C) was demonstrated to be a superior nMOSFET stressor compared to SMT or tensile liner (TL) stressors. eSi:C nMOSFET showed higher channel mobility and drive current over our best poly-gate 45nm-node nMOSFET with SMT and tensile liner stressors. In addition, eSi:C showed better scalability than SMT plus tensile liner stressors from 380nm to 190nm poly-pitches.