Investigation of a dual MOSCAP TFET with improved vertical tunneling and its near-infrared sensing application

摘要

In this work, a delta-doped dual MOS-capacitor (MOSCAP) (D-MOS) tunnel field effect transistor is proposed and investigated. The investigation has been carried out by varying the mole fraction of the SiGe delta-layer as well as by optimizing device dimensions like the effective oxide thickness, elevated channel thickness and epi-layer (thin intrinsic layer of the MOSCAP region) length and thickness. The optimized proposed device offers an ON current of 6.91 x 10(6) A mu m(-1), I-ON/I-OFF of 4.83 x 10(8), average sub-threshold swing of 18.67 mV dec(-1) and a maximum cut-off frequency of 1.28 x 10(9) Hz. Furthermore, the application of the proposed device as a near-infrared optical sensor is studied using a photosensitive gate. It is observed that the device can sense closely spaced spectral wavelengths (similar to 100 nm) in the near-infrared region of the spectrum (1-0.7 mu m) at low intensity of illumination (1 W cm(-2)). The peak spectral sensitivities of 4.67 x 10(3), 3.3 x 10(3) and 9.77 x 10(2) for the wavelength pairs (0.8 mu m-0.7 mu m), (0.9 mu m-0.8 mu m) and (1 mu m-0.9 mu m), respectively, are observed making it a highly sensitive optical sensor.