Improved GaAs/In_0.25Ga_0.75As/GaAs pseudomorphic heterostructure by growing double δ-doping GaAs layers on both sides of the channel

A novel GaAs/In_0.25Ga_0.75As/GaAs heterostructure field effect transistor with δ-doping of the GaAs on both sides of the InGaAs channel has been grown by low-pressure metalorganic chemical vapor deposition (LP-MOCVD). Very high two dimensional electron gas (2DEG) concentration of 5.1 and 3.4 × 10¹² cm^-2 at 300 and 77 K respectively, along with enhanced electron mobilities of 4500 and 14100 cm²/v·s at 300 and 77 K respectively, were achieved. A maximum extrinsic transconductance of 140 mS/mm and a high saturation current density of 460 mA/mm at 300 K for a gate length of 2 μm, were obtained. A broad transconductance region extending from reverse to forward gate bias was observed due to the double δ-doped GaAs grown symmetrically on both sides of the channel.