ENHANCED 2-DIMENSIONAL ELECTRON-GAS CONCENTRATIONS AND MOBILITIES IN MULTIPLE DELTA-DOPED GAAS/IN0.25GA0.75AS/GAAS PSEUDOMORPHIC HETEROSTRUCTURES

Selectively multiple delta-doped GaAs/In0.25Ga0.75As/GaAs pseudomorphic heterostructures grown by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) for improving two-dimensional electron gas (2DEG) concentrations and mobilities were demonstrated. All the multiple delta-doped structures revealed significantly higher 2DEG concentration and mobility than those of single delta-doped and conventional homogeneously doped GaAs/InGaAs structures. The structure with double delta-doped GaAs layers grown symmetrically on both sides of the channel showed extremely high 2DEG concentrations of 6.2(4.1) x 10(12) CM-2 and mobilities of 4630(19100) cm2/V.s at 300(77) K. Meanwhile, a peak extrinsic transconductance of 390 mS/mm, maximum effective saturation current density of 880 mA/Mm, with broad and high transconductance region at 300 K, were achieved in this symmetrically delta-doped GaAs structure.