Modeling and study of two-BDT-nanostructure based sequential logic circuits

In this paper, study of different digital logic circuits developed using two-BDT ballistic nanostructure is presented. New D flipflop (DFF) based on the same nanostructure is also proposed. The logic structure comprises two ballistic deflection transistors (BDTs) that are experimentally proven to operate at Terahertz frequencies. The non-linear behavior of the BDT's transfer characteristic has been perfectly reproduced by means of Monte Carlo simulations, where a specific attention has been devoted to surface charges. An analytical model built on the results of advanced MC simulations has been integrated into a behavioral Verilog AMS module to confirm the functionality of the circuit design. The module is used to analyze operating conditions of different combinational circuits and to investigate the feasibility of DFF design using BDT nanostructure. The simulation results indicate successful operation of both combinational and sequential circuits developed using two-BDT logic structure under proper biasing of gate and source terminals. The operating voltages of the proposed DFF are estimated to be ± 225mV.