RESUMEN
Corner-effect existing in L-shaped tunnel field-effect-transistor (LTFET) was investigated using numerical simulations and band diagram analysis. It was found that the corner-effect is caused by the convergence of electric field in the sharp source corner present in an LTFET, thereby increasing the electric field in the sharp source corner region. It was found that in the corner-effect region tunneling starts early, as a function of applied bias, as compared to the rest of the channel not affected by corner-effect. Further, different tunneling regimes as a function of applied bias were identified in the LTFET including source to channel and channel to channel tunneling regimes. Presence of different tunneling regimes in LTFET was analytically justified with a set of equations developed to model source to channel, and channel to channel tunneling currents. Drain-current-gate-voltage (Ids-Vgs) characteristics obtained from the equations is in reasonable qualitative agreement with numerical simulation.
RESUMEN
A simple to implement model is presented to extract interface trap density of graphene field effect transistors. The presence of interface trap states detrimentally affects the device drain current-gate voltage relationship Ids-Vgs. At the moment, there is no analytical method available to extract the interface trap distribution of metal-oxide-graphene field effect transistor (MOGFET) devices. The model presented here extracts the interface trap distribution of MOGFET devices making use of available experimental capacitance-gate voltage Ctot-Vgs data and a basic set of equations used to define the device physics of MOGFET devices. The model was used to extract the interface trap distribution of 2 experimental devices. Device parameters calculated using the extracted interface trap distribution from the model, including surface potential, interface trap charge and interface trap capacitance compared very well with their respective experimental counterparts. The model enables accurate calculation of the surface potential affected by trap charge. Other models ignore the effect of trap charge and only calculate the ideal surface potential. Such ideal surface potential when used in a surface potential based drain current model will result in an inaccurate prediction of the drain current. Accurate calculation of surface potential that can later be used in drain current model is highlighted as a major advantage of the model.