Influence of Spacer Thickness on the Noise Performance in InP HEMTs for Cryogenic LNAs

InP high electron mobility transistors (InP HEMTs) with different spacer thickness 1 to 7 nm in the InAlAs-InGaAs heterostructure have been fabricated and characterized at 5 K respect electrical dc rf properties. The HEMT noise performance was extracted from gain measurements of a hybrid low-noise amplifier (LNA) equipped discrete transistors. When biased for optimal operation, LNA using HEMTs achieved lowest average temperature 1.4 4–8 GHz. channel estimated drain which confirmed minimum HEMT. It is suggested that acts control degree real-space transfer electrons barrier responsible observed variation cryogenic HEMTs.