STATIC DOMAIN IN A TRANSFERRED-ELECTRON DEVICE BASED ON GRADED-GAP AlGaAS
І. P. Storozhenko · Telecommunications and Radio Engineering · 2016
The usage of the varyband semiconductors in uniformly doped devices with intervalley electron transfer effect can result in the formation of a static electric domain. Keen interest in the static domain is due to the possibility of creating local electric field strength sufficient for zone-zone impact ionization. Diodes with avalanche ionization in the static domain can be used as active elements of noise generators. The paper analyzes the process of the static domain formation and avalanche current in it on the basis of a two-temperature model of varyband AlGaAs. It is shown that for a static domain formation at room temperature, two conditions are required. First, the minimum value of the energy gap between the Γ-valley and the closest to it in side valley by energy should be smaller than the thermal energy of the electrons. Secondly, the rate of change of the energy gap with coordinate must be greater than 150 eV·m-1. Accordingly, in the devices based on Al0.36Ga0.64As–GaAs cathode static domain is formed, and in the devices on the basis of GaAs-Al0.36Ga0.64As anode domain is formed. Varyband semiconductor compounds in which the static domain may form has been determined. The usage of graded-gap Al0.36Ga0.64As–GaAs compound with low doping level near the cathode increases the effective and integral current-multiplication factors as compared to GaAs-diode. The findings expand the knowledge of the physical processes of carrier transport in complex semiconductor structures. They can be used for technological development of new high-speed devices, such as transistors, diodes, Gunn diodes with a static domain, avalanche transit-time diodes, frequency multipliers.