Metamorphic AlInAs/GaInAs HEMTs on GaAs Substrates by MOCVD

Metamorphic AlInAs/GaInAs high-electron mobility transistors with very good device performance have been grown by metal-organic chemical vapor deposition (MOCVD), with the introduction of an effective multistage buffering scheme. Measured room-temperature Hall mobilities of the 2-DEG were over 8000 cm
²
/V ldr s with sheet carrier densities larger than 4 times 10
¹²
cm
^-2
. Transistors with 1-mum gate length exhibited transconductance up to 626 mS/mm. The unity current gain cutoff frequency f
_T
and the maximum oscillation frequency f
_max
were 39.1 and 71 GHz, respectively. These results are very encouraging toward the manufacturing of metamorphic devices on GaAs substrates by MOCVD.