Modeling of the Emission/Noise Temperature in MOSFET/HEMT Structures

A generalization of the approach which describes the emission capabilities of micron and submicron semiconductor structures in terms of the spectrum of thermally non-equilibrium noise/emission temperature is considered for the case of three-terminals FET/HEMT structures. By using, in the framework of hydrodynamic approach, a direct numerical modeling of the frequency dependence of the components of the small-signal impedance/admittance and spectral densities of voltage/current fluctuations at FET/HEMT terminals, it is shown that: (i) in contrast with two-terminal devices (diodes) the emission capabilities of FET/HEMT cannot be characterized by a single spectrum of the noise/emission temperature, and (ii) the character of the noise/emission temperature spectrum depends on both the choice of the FET/HEMT loading circuit which contains the emitting antenna (source-to-drain or source-to-gate) and the operation mode (constant current or constant voltage) of the accompanying non-emitting external circuit.