COMPARATIVE-ANALYSIS OF MICROWAVE NOISE IN GAAS AND ALGAAS GAAS CHANNELS

Hot electron noise at 10 GHz microwave frequency is investigated in an AlGaAs/GaAs heterostructure channel with two-dimensional electron gas (2DEG), and the results are compared to those for 3DEG channels of Ga As. An experimental evidence of noise due to 2DEG reversible 3DEG tran sfer at 80 K is presented. The related longitudinal diffusion of hot e lectrons in long 2DEG channels is found to dominate at the intermediat e fields which are well below the threshold field for intervalley diff usion in GaAs. A tendency to suppress the intervalley noise and diffus ion by the 2DEG reversible 3DEG transfer is observed at the high field s. Possible suppression of the dominant sources of microwave noise in modulation-doped field-effect transistor channels is discussed.