Technology Computer‐Aided Design and Performance Analysis of a Ge/Si Extended‐Source Asymmetric Cladding‐Layer Tunnel Field‐Effect Transistor Biosensor Toward Low‐Power Wearable Sports‐Training Biomarker Monitoring

Low‐power wearable sports‐training monitoring requires compact and sensitive biosensing units for potential biomarker‐related physiological assessment during exercise and recovery. In this work, a Ge/Si extended‐source asymmetric cladding‐layer tunnel field‐effect transistor biosensor is proposed and investigated using two‐dimensional technology computer‐aided design simulation. The device employs a Ge source, Si channel/drain, and heavily doped p + Si cladding layers to induce charge plasma near the source region. Two asymmetric sensing nanocavities are introduced around the cladding‐layer/source region, enabling dielectric modulation of both the main source‐side tunneling path and the extended‐source‐assisted tunneling region. Representative biomolecule cases are used to evaluate dielectric‐ and charge‐modulated electrical transduction rather than analyte‐specific recognition of a particular sports‐training biomarker. The results show that higher biomolecule permittivity enhances drain current, improves the I ON / I OFF ratio, and reduces point subthreshold swing (SS). For k = 8, the biosensor achieves a maximum drain current sensitivity of 2.06 × 10 5 , an I ON / I OFF ratio of 9.55 × 10 5 , and a point SS of 26.72 mV/dec at V DS = 0.4 V. Under negatively charged biomolecule conditions at k = 6.3, the current sensitivity reaches 1.04 × 10 6 . The results indicate its potential as a device‐level sensing unit for future low‐power wearable sports‐training biomarker monitoring platforms.