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DS: Fachverband Dünne Schichten
DS 11: Focus Session: Sensoric Micro and Nano-systems I
DS 11.10: Talk
Tuesday, April 1, 2014, 12:45–13:00, CHE 89
Limitations of signal to noise ratio in Schottky barrier FET based biosensors — •Sebastian Pregl1,2,3, Larysa Baraban1, Walter Weber2, Thomas Mikolajick4,2,3, and Giovanni Cuniberti1,3 — 1Institute for Materials Science and Max Bergmann Center of Biomaterials TU Dresden 01062 Dresden, Germany — 2Namlab GmbH 01187 Dresden, Germany — 3Center for Advancing Electronics Dresden (cfaed) TU Dresden 01062 Dresden, Germany — 4Institute of Semiconductor and Microsystems TU Dresden 01187 Dresden, Germany
In field effect transistor (FET) based biological sensors the presence of the specimen is detected via determination of changes of the electrical potential on the sensor surface. The resolution is limited by the accuracy of the transistor source to drain current measurement. Therefore a high ratio of transconductance to current noise is desired to maximize the signal to noise ratio (SNR). Schottky barrier FETs suffer from a high serial resistance which increases the noise level in transistor regimes beyond the subthreshold. Here, a study is presented reflecting the scaling of important device parameters like threshold voltage, transconductance, current noise and subthreshold slope with respect to the nanowire length. Regarding these dependancies a compromise of transistor size to SNR can be found matching the demands of the particular measurement.