Exploitable results Microwave and Low Frequency Noise Spectroscopy of Two-Dimensional Electron Gas Channels (NOISE) Combined with response measurements and Monte Carlo simulation, the NOISE spectroscopy is a tool for optimisation of NOISE-speed performance of HFET (Heterostructure Field Effect Transistor) channels, ensuring quality control and feedback to epitaxial technology and miniaturisation for new generation of low-noise microwave devices. Equivalent noise temperature and spectral density of current (voltage) fluctuation is measured on test structures and transistors to determine dependence of noise spectra on band structure, doping level, electric field strength, channel length and ambient temperature at frequencies ranging from 0.1 Hz to 10 GHz. Together with traditional sources of excess noise resulting from 1/f fluctuations, generation-recombination transitions, and intervalley transfer of hot electrons, the sources specific to two-dimensional electron gas - intrasubband and intersubband and real-space transfer transverse tunneling - have been resolved. The Hooge parameter is determined for Al-free and Al-containing, lattice-matched and strained, InP-based InGaAs 2DEG channels, the lowest value reaching 1.5 10-5.. Activation energies of traps located in heterojunction channels are determined from generation-recombination noise spectra measured at intermediate/high frequencies and different ambient temperatures. At microwave frequencies, hot electron real-space transfer noise is resolved in AlGaAs/GaAs, AlInAs/InGaAs/AlInAs and InP/InGaAs/InP channels, the associated time constant is found to exceed few picoseconds. Transverse tunneling time constant determined from noise measurement for AlGaAs/GaAs/AlAs/GaAs is 10-15 ps. The shortest time constant determined from noise spectroscopy data is 30-60 fs for intervalley Gamma-X transfer in GaAs. The developed method of NOISE spectroscopy has shown itself to be a powerful tool for studying kinetic processes in quantum well structures, and for improving speed-noise tradeoff and response characteristics of heterostructures designed for low-noise microwave electronics. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
