Reliability of 50 nm low-noise metamorphic HEMTs and LNAs

The long-term stability of a 50 nm low-noise metamorphic HEMT technology has been investigated by biased accelerated lifetime tests on both MHEMT devices and two-stage LNAs for W-band applications. The lifetime tests were performed at three channel temperatures, a drain voltage of 1 V and a power density of 0.3 W/mm in air. Based on a -10% degradation of g(ind m max) failure criterion an activation energy of 1.6 eV and a projected median lifetime of 2.7 x 10(exp 6) h at T(ind ch) =125 deg C were determined. The two-stage LNAs were stressed at a channel temperature of 185 deg C for 4000 h. The S-parameters did not show any significant degradation after 4000 h of stress time if the positive threshold voltage shift was compensated for by a corresponding increase of the gate voltage. The reliability results demonstrate the stable operation of 50 nm MHEMTs and LNAs for W-band applications and beyond.