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 pseudomorphi c heterostructures grown by low-pressure metalorganic chemical vapor d eposition (LP-MOCVD) for improving two-dimensional electron gas (2DEG) concentrations and mobilities were demonstrated. All the multiple del ta-doped structures revealed significantly higher 2DEG concentration a nd mobility than those of single delta-doped and conventional homogene ously doped GaAs/InGaAs structures. The structure with double delta-do ped GaAs layers grown symmetrically on both sides of the channel showe d extremely high 2DEG concentrations of 6.2(4.1) x 10(12) CM-2 and mob ilities of 4630(19100) cm2/V.s at 300(77) K. Meanwhile, a peak extrins ic 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.