Metamorphic AlInAs/GaInAs HEMTs on silicon substrates by MOCVD

Metamorphic Al0.50In0.50As/Ga0.47In0.53As high electron mobility transistors (mHEMTs) grown by Metal Organic Chemical Vapor Deposition (MOCVD) on n-type silicon substrates with introduction of a novel multi-stage buffering stack scheme have been fabricated for the first time. 1.0-μm-gate-length depletion-mode mHEMTs with maximum transconductance up to 613 mS/mm are achieved. The unity current gain cut-off frequency (fT) and the maximum oscillation frequency (fmax) are 36.9 and 55.6 GHz, respectively. This device has the highest fT yet reported for 1.0-μm-gate-length HEMTs grown on silicon by MOCVD. Also, this performance is comparable to that of similar GaAs-based mHEMTs. These are encouraging initial results leading to the manufacturing potential of integrated high-speed metamorphic devices for logic applications on silicon substrates by MOCVD.