Performance Investigation of GaSb/Si Heterojunction Based Gate Underlap and Overlap Vertical TFET Biosensor.

The present paper estimates the performance of vertically developed double gate GaSb/Si tunnel field-effect transistor (V-DGTFET) biosensor with source pocket. A commercially accessible tool, Silvaco-TCAD, is exploited for carrying simulations of V-DGTFET. The device's novelty is deploying a material with a small bandgap, namely GaSb, in the source region to improve the carrier tunneling in source-channel (GaSb-Si) heterojunction. Further, the present work has analysed the performance on half gate underlap and half gate overlap V-DGTFET based label-free biosensor. The performance of V-DGTFET biosensor corresponding to various biomolecules such as APTES with κ = 3.57 , bacteriophage-T7 with κ = 6.4 , apomyoglobin with κ =8.1 and gelatin with κ = 12 is investigated with reference to energy band diagram, potential profile, electric field and drain characteristics. Furthermore, by considering the different values of dielectric constants from 1 to 12, the present paper computed the figure of merits (FOMs) essentially linearity and sensitivity. The results demonstrated that neutral biomolecules with higher dielectric constant values showed higher sensitivity compared with other biomolecules. Moreover, it is estimated that gelatin has to drain current sensitivity of 5.6×105 , which is 13%, 20%, and 41% more in comparison to apomyoglobin ( κ = 8.1 ), bacteriophage-T7 ( κ = 6.4 ), and APTES ( κ = 3.57 ) sensitivity at 15 nm cavity length.