Monte Carlo calculation of noise and small-signal impedance spectra in submicrometer GaAs n(+)nn(+) diodes

The time-and-frequency behavior of hot-carrier noise in submicrometer n(+)nn(+) GaAs diodes is investigated theoretically using the Monte Carlo method. We have continuously investigated the noise from current-to-voltage operation mode by calculating the noise-power spectrum at the terminals of a noiseless load-resistance R connected in series with the diode. By varying appropriately the value of R we have calculated the small-signal impedance of the diode and then obtained the full spectrum of the noise temperature. tinder voltage-operation mode the current-noise spectrum exhibits two resonant peaks at the transit-time and plasma frequencies, respectively. Under current operation mode, all current oscillations are effectively damped, and the voltage-noise spectrum exhibits a quasi-lorentzian shape, which vanishes at the transit-time frequency. The behavior of hot-carrier noise closely parallels the frequency dependence of the diode small-signal impedance, which exhibits a dynamic negative differential resistance in the frequency range corresponding to the transit-time resonance. (C) 1996 American Institute of Physics.