Modeling and simulation study of different FET and TFET architectures for bio-sensing and gas-sensing applications
Though the revolution in semiconductor industry started with silicon based MOS devices, but MOSFETs are rapidly approaching towards its theoretical limit of operation. Continuous down-scaling of conventional MOSFETs led to power crisis and also gives rise to Short Channel Effects (SCEs) like hot electron effect, drain induced barrier lowering (DIBL), velocity saturation, surface scattering, impact ionisation etc. and another major issue is subthreshold swing for this device cannot be brought below 60mV/dec at room temperature. A strong contender to replace MOSFET based devices and enhance the device performance is Tunnel Field Effect Transistor (TFET) which has the potential to achieve lower subthreshold swing and low off current. These MOSFET and TFET based devices are also used for bio-sensing and gas-sensing applications. Though various devices (e.g.- optical detector) are available for label free detection of biomolecules TFET based biosensors becomes popular due to low cost, their ability to detect both charged and neutral biomolecules and their effectiveness. Similarly for gas-sensing application FET based devices are being preferred over existing chemical detectors. In this work performance of different FET and Tunnel FET based architectures for bio-sensing and gas-sensing application are investigated and compared in terms of their ID-VG, ID-VD curves, variation of threshold voltage and sensitivity. And an analytical model for dielectric modulated junctionless TFET bio-sensor has been developed.
Keywords: MOSFET, tunnel FET, dielectric modulated TFET, analytical modeling, bio-sensor, gas-sensor