Properties Of Semiconductor Nano Electronics Design And Terahertz Detection

As MOSFETs are scaled into nanometer regime, new materials and new structures have beendevelopment rapidly, in order to further improve the field effect transistor device performance, thehetero-material-gate (HMG) structure, lightly doped drain and source (LDDS) structure and lineardoping applied to CNTFET. By constructing a quantum kinetic model, studied the effect of thehetero-material-gate, lightly doped drain and source and linear doping on the transport properties ofdevice.The main contents of this paper are:The hetero-material-gate MOSFET structure with the lightly doped drain and source(LDDS-HMG-MOSFET) is used finite element method to calculate electrical characteristics, andstudy the effects of HMG and LDDS on the electrical properties of this new structure. The resultsshow that the HMG structure can reduce the leakage current of MOSFET, so it can improve theon-off current ratio, and inhibit the DIBL effect. The LDDS structure can increase the effectivechannel length of device, so it can reduce the band to band tunneling effect (BTBT).The electrical characteristics of two kinds of new structures have presented, one is thehetero-material-gate carbon nanotube field effect structure with lightly doped drain and source(LDDS-HMG-CNTFET). Another is the hetero-material-gate graphene field effect transistor withlinear doping (DL-GNRFET). And compared to the electrical properties of field effect transistorinclude three kinds of materials such as silicon, carbon nanotubes and grapheme. The results showthat LDDS-HMG-CNTFET has a lower leakage current, excellent switching characteristics, betterability in suppressing DIBL effect and short channel effect, and improves transmission efficiencyand suppresses hot electron effect. DL-GNRFET has a lower leakage current, a larger cutofffrequency, and improves transmission efficiency and suppresses BTBT effect.The terahertz detection response is calculated by fluid mechanics theory and based on theplasma fluctuation mechanism. The results show that, when the terahertz wave is radiated on thefield effect transistor source, under certain boundary conditions, a DC voltage is appeared betweenfield effect transistor source and drain, and the DC voltage is relevant to the frequency andamplitude of terahertz radiation.