GaAs/AlGaAs quantum well and modulation-doped heterostructures grown by organometallic vapor phase epitaxy using trimethylamine alane

Abstract

High-quality GaAs/AlGaAs quantum well and modulation-doped heterostructures have been grown by low-pressure organometallic vapor phase epitaxy (OMVPE) using trimethylamine alane (TMAA) as a new aluminum source. TMAA is an alternative to the conventional organometallic precursors and offers the advantage of substantially reduced oxygen and carbon incorporation in AlGaAs. Intense photoluminescence (PL) with narrow linewidths at 2 K was observed from multiple quantum well samples with well widths of 1.5-10 nm. Transmission electron microscopy of a fifty period superlattice (4 nm GaAs/44 nm Al 0.18Ga0.82As) revealed abrupt interfaces and excellent well-to-well thickness uniformity. Selectively doped heterostructure transistors (SDHTs) fabricated on the modulation-doped structures exhibited a maximum extrinsic transconductance of 339 mS/mm for a 1-μm-gate length at 300-K, the highest reported for OMVPE grown devices. A unity current gain cutoff frequency, ft, of 16 GHz and a maximum frequency of oscillation, f max, of 23 GHz were obtained for these SDHTs.