CIRCUITS AND SIMULATIONS AT 1 THZ

The current state-of-the-art in device and circuit simulation, design and application for semiconductor devices operating in the terahertz r egime is reviewed. The evolution of physical models to describe and in vestigate tunnelling and other ultra-small device structures is descri bed. Simulations based on quantum hydrodynamic models and self-consist ent solutions of the Poisson and Schrodinger equations, using analytic al and numerical techniques are considered. Equivalent circuit extract ion methods are considered, together with device models up to 2 THz. E xamples of results obtained from simulations of terahertz devices are given, including resonant tunnelling structures. The design and modell ing of circuits incorporating semiconductor tunnelling devices is disc ussed and illustrated with examples of recent developments. The challe nges facing circuit designers and the potential applications for this technology are highlighted.