Gate Sinking Effect of 0. 1 μm InP HEMT MMICs Using Pt/Ti/Pt/Au

Gate sinking effect of 0.1 mum InAlAs/InGaAs/InP HEMT MMICs (with Pt/Ti/Pt/Au gate metals) subjected to elevated temperature lifetests has been investigated. The results show that Pt sinking is the dominant degradation mechanism caused by Pt diffusing into the In
_0.52
Al
_0.4
As Schottky barrier layer. Pt sinking explains the observed evolutions of Schottky diodes, Ids-Gm transfer characteristics, and the S21 increase. Scanning-transmission-electron-microscope micrographs substantiate the alleviation of Schottky junction degradation of InP HEMTs using Pt/Ti/Pt/Au gates. Moreover, 2-temperature lifetest shows that the activation energy is approximately 1.55 eV, based on a failure criterion of DeltaI
_DSS
= -20%. The results from this study demonstrate that Pt sinking is the primary degradation mechanism of 0.1 mum InP HEMT MMICs with Pt/Ti/Pt/Au gate metals