EFFECT OF SCHOTTKY-BARRIER ALTERATION ON THE LOW-FREQUENCY NOISE OF INP-BASED HEMTS

For the first time the effect of increasing the Schottky barrier's Al content of InP-based InAlAs-InGaAs HEMT's from 48 to 60% on the low-fr equency (LP) drain and gate current noise is investigated. It is shown that the LF gate current noise S-IG (f) for the 60% case decreases by almost three decades, while the LF drain current noise S-IDS(f) stays at the same level. From small coherence values, it can be concluded t hat drain and gate noise sources can be treated separately which facil itates the LF noise modeling of these HEMT's.