Advanced Micron Sized Gunn Diode Based on Graded-Gap GaPAs – GaInAs

Abstract

The paper studies the characteristics of Gunn diodes based on graded-gap GaInPAs semiconductor. Gunn diodes are active elements for generating electromagnetic waves in the millimeter and submillimeter ranges. Nowadays, providing modern equipment with active sources of the subterahertz range is an urgent task. It can be implemented by increasing Gunn diodes power and cutoff frequencies of generation. One of the means to increase the cutoff frequency of Gunn diodes is the use of graded-gap semiconductors. The dependence on the coordinate of many parameters of a graded-gap semiconductor affects the processes that occur in the Gunn diode based on the graded-gap semiconductor. Therefore, it is very important to optimize the diode structure by both the doping level and varying the fraction parts of the graded-gap alloy. The paper presents the results of modeling the operation of Gunn diodes with an active zone length of 1 μm based on graded-gap GaPAs -GaInAs alloy at different lengths of the graded-gap layer, different fraction parts of In and P and different electron densities in the active zone. The power spectra of self-oscillations (in the absence of a resonator) of Gunn diodes are obtained, the analysis of physical processes is performed, the optimal lengths of the graded-gap semiconductor layer and optimal mole fractions of In and P are found to obtain the highest power and oscillation frequency. For diodes with an electron density in the active zone of 6×10 16 cm -3 , Ga0.67P0.33As -Ga0.5In0.5As has the greatest oscillation power at the layer length of the graded-gap compound equal to 0.2 m. This diode provides an RF power of 11.28 mW at 102.5 GHz for the fundamental harmonic and 49 W (307.5 GHz) for the third harmonic.