High sensitivity Ge-source L-shaped tunnel BioFETs for detection of high-K biomolecules

BioFETs have potential applications in detecting various kinds of pathogens due to their label free and highly stable detection of biological species with high responsivity and reliability. This paper investigates detection of different types of high-k biomolecules using Ge-source L-tunnel field effect transistor in the presence of watery medium. The entire detection scheme relies on the tunneling effect at Ge-source and Si-channel junction for introducing various types of biomolecules through the vertical arm of ‘L’ which is used as the cavity, the main sensing area of the device. The device characteristics are affected by the dielectric constant of the biomolecules. TCAD tools are used to obtain the results. In addition, the impact of doping concentration of the source, drain and substrate on sensitivity is investigated. Furthermore, effects of the variation of source height and temperature on sensitivity of the sensor are studied. We achieve 48.46% improvement in sensitivity using the aforesaid device which is pretty high compared to Si based structure. Our findings suggest that use of Ge-source in LTFET yields far better sensitivity than Si based and many other devices reported earlier.