The inputs to the VSCNFET model are the physical device design including device dimensions, CNT diameter, gate oxide thickness, etc. Parasitic effects are modeled: (i) direct source-to-drain and band-to-band tunneling current calibrated by numerical simulations (ii) metal-to-CNT contact resistances calibrated by experimental data (iii) parasitic capacitance including gate-to-CNT fringe capacitances and gate-to-contact coupling capacitances. The intrinsic drain current (Id) and terminal charges are based on the virtual source (VS) model, with the virtual source velocity extracted from experimental data for different channel lengths (ranging from 3-um down to 15-nm). capacitance-voltage) characteristics in a short-channel metal-oxide-semiconductor field-effect transistor (MOSFET) with carbon nanotubes as the channel material. The Stanford Virtual-Source Carbon Nanotube Field-Effect Transistors (VSCNFET) model is a semi-empirical model that describes the current-voltage and charge-voltage (i.e. VGSth ) is kept constant and VDS is increased from 0 to a more positive voltage Enhancement-Type MOSFET Transfer Curve To determine ID given VGS: Where: VT = threshold voltage or voltage at which the MOSFET turns on k = constant found in the specification sheet 2 TGSD )VV(kI p-Channel Enhancement-Type MOSFETs The p-channel enhancement-type MOSFET is similar to the n-channel, except that the voltage polarities and current directions are reversed.Stanford University Virtual Source CNFET Model Output characteristic curve for n-channel JFET \ Water analogy for the JFET control mechanism 6.2 JFET Construction Transfer characteristic curve of n- channel JFET: pinch off voltage: Vp Water analogy for the JFET control mechanism loss 8 FET 6.2 JFET Construction VGS -Control the flow of water (charge) to the drain VDS -the applied voltage from drain to source like the source of water pressure. FETs are less sensitive to temperature variations and because of their construction they are more easily integrated on ICs. FETs also have a higher input impedance.FETs are voltage controlled devices whereas BJTs are current controlled devices.Download ch6 Field-Effect Transistors.ppt and more Engineering Lecture notes in PDF only on Docsity!Chapter 6: Field-Effect Transistors FETs (Field-Effect Transistors) are much like BJTs (Bipolar Junction Transistors).
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