a‐Si:H temperature sensor integrated in a thin film heater

In this work we present an hydrogenated amorphous silicon (a-Si:H) temperature sensor integrated in a thin film heater to perform biomolecular treatments. The system is fabricated on a microscope glass slide and includes a PolyDiMethylSiloxane (PDMS) chamber to confine the solution containing the sample and to avoid its evaporation. The heater is a 200nm-thick titanium/tungsten sputtered film with a serpentine shaped geometry that has been designed by a finite element simulator in order to obtain a spatial-uniform temperature distribution. A uniformity better than 3% has been achieved over the surface of the structure. The temperature sensor is a n-type/intrinsic/ p-type a-Si:H stacked structure deposited by plasma enhanced chemical vapor deposition. The top and bottom contacts of the diode are made by the same metal utilized to fabricate the heater. The characterization of the sensor response has been performed both under forward and reverse bias condition. In reverse bias condition, at fixed voltage, the current-temperature curve exhibits an exponential behavior. In forward bias condition, at constant bias current, the voltage across the diode is linearly dependent on the temperature in the range 30-90 °C. In particular, using a constant bias current of 10 nA, a sensitivity around -3.3 mV/°C has been achieved.

[1]  V. V. Baranov,et al.  Properties of titanium-tungsten thin films obtained by magnetron sputtering of composite cast targets , 1995 .

[2]  A. Woolley,et al.  Ultra-high-speed DNA sequencing using capillary electrophoresis chips. , 1995, Analytical chemistry.

[3]  Jing Cheng,et al.  A microchip-based PCR device using flexible printed circuit technology , 2005 .

[4]  J. Köhler,et al.  Temperature Controlled Chip Reactor for Rapid PCR , 1998 .

[5]  Yong-Kweon Kim,et al.  Application of a temperature-controllable microreactor to simple and rapid protein identification using MALDI-TOF MS. , 2006, Lab on a chip.

[6]  Christopher R. Lowe,et al.  Silicon microchambers for DNA amplification , 1998 .

[7]  I-Ming Hsing,et al.  Microfabricated PCR-electrochemical device for simultaneous DNA amplification and detection. , 2003, Lab on a chip.

[8]  Alberto Escarpa,et al.  Real sample analysis on microfluidic devices. , 2007, Talanta.

[9]  L J Kricka,et al.  Chip PCR. II. Investigation of different PCR amplification systems in microbabricated silicon-glass chips. , 1996, Nucleic acids research.

[10]  I M Hsing,et al.  A miniaturized DNA amplifier: its application in traditional Chinese medicine. , 2000, Analytical chemistry.

[11]  R. Gibbs,et al.  The Polymerase Chain Reaction , 1994, Birkhäuser Boston.

[12]  Ralf Lenigk,et al.  Genotyping on a complementary metal oxide semiconductor silicon polymerase chain reaction chip with integrated DNA microarray. , 2002, Analytical chemistry.

[13]  Alan G. R. Evans,et al.  Closed chamber PCR-chips for DNA amplification , 2000 .

[14]  Bingcheng Lin,et al.  Simply and reliably integrating micro heaters/sensors in a monolithic PCR‐CE microfluidic genetic analysis system , 2009, Electrophoresis.

[15]  Ulrich Dillner,et al.  Chip elements for fast thermocycling , 1997 .