A Judicious Exploitation of Electrical Characteristics of a Unique GeSn TFET With Corner-Point for Sensing S-Protein Biomarker

Abstract

In this paper, for the first time, a unique Ge _(1-x) Sn _x alloy-based TFET sensor with a deliberate corner-point in the channel has been proposed for successful detection of S-protein, a significant biomarker. After the validation of our simulation scheme through a process of calibration of an experimentally realized mother GeSn TFET device, the same is turned into the proposed sensor device by suitably creating nanogap cavity in it. The performance of the proposed sensor device has been thoroughly investigated as a function of channel epilayer thickness (CH _epi ) in terms of a set of performance metrics – P-responsivity and P-sensitivity. Then, by varying the mole-fraction of Ge _(1-x) Sn _x in the proposed sensor, the sensing performance has been studied in terms of the aforementioned performance metrics, along with an additional unique metric known as dynamic sensitivity. Interestingly, it has been observed that the most suitable device in pure electronic domain (digital or analog) is the least suited in sensing domain and vice-versa. This forbids the tendency of blind-picking of device with enhanced performance in pure electronic domain for sensing purpose as well without proper investigation. After a thorough analysis, it is observed that the proposed sensor with CH _epi = 10 nm has evolved as the most optimized sensor device while the choice of mole-fraction remains application specific. Also, the ultimately optimized sensor shows a fairly good performance in dealing with the real-time position variability aspect (even if it is due to the repulsive steric effects of S-protein molecules) which results in a partial hybridization issue.