Linear and nonlinear analysis of microwave power generation in submicrometer n+nn+ InP diodes

Abstract

A closed hydrodynamic model and the associated numerical procedures are developed for simulating hot-carrier transport in submicron semiconductor devices. To check the validity of the model, the steady-state characteristics of near-micron n+nn+ InP diodes are compared with a standard Monte Carlo approach. The excellent agreement found fully validates the physical reliability of our model which has been further developed to investigate linear and nonlinear time-dependent characteristics. The contribution of each part of the device, when operating as microwave power-generation, is analyzed through the spatial profiles of the impedance-field spectrum. The usual subdivision of the n-region into a passive (dead-zone) and active zone is carried out. The dead zone is found to manifest itself as a purely real resistance which is practically independent of the frequency. One or more spatial zones which are responsible for the generation are shown to be formed in the active region of the diode. By reducing the length of the n-region, under the condition that the total current is constant in time, the additivity of the contributions from each part of the device into the generation spectrum is proven. The predictions of the linear analysis are compared with a direct simulation of the diode performance in the external resonant circuit. A wide-band tuning of the generation frequency from 100 up to 200 GHz is demonstrated. The microwave power generation is shown by both hydrodynamic and Monte Carlo simulation to be caused by the formation and propagation through the diode of accumulation layers. Theoretical results are found to compare well with available experiments.