“…The most commonly reported degradation mechanisms for both GaAs and InP-based HEMTs include contact problems (such as sinking gates in which the gate metal begins to react with the underlying semiconductor), creation of surface states (which can be manifested as what is commonly called gate lag), hot carrier-induced (impact ionization at gate edge), mechanical stress (the absorption of H into Ti-based Schottky gates can lead to compressive stress due to piezo effects in the semiconductor) [ 3 ], or avalanche breakdown in the semiconductor, fluorine contamination, and corrosion (mainly related to Al oxidation) [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. Metamorphic HEMT (MHEMT) technology has been developed using metamorphic buffer layers to grow InAlAs/InGaAs on larger diameter GaAs substrates to overcome the limitations of InP substrates: smaller wafer size, higher cost, and brittle nature.…”