OMVPE-gezüchtete AlxGa1-x0.5In0.5P/InGaAs MODFET-Strukturen - Züchtungstechnik und Hallbeweglichkeit

: Bachem, K.H.; Fekete, D.; Pletschen, W.; Rothemund, W.; Winkler, K.

Abstract
Modulation doped (AlsubxGasub1minussubx)sub0.5 Insub0.5P/InsubyGasub1minussubyAS/GaAs single quantum well structures have been grown by low pressure metal organic vapour phase epitaxy and characterized by Hall measurements and cathodoluminescence. The high conduction band offset in this structure is favourable for the fabrication of MODFET structures with high two-dimensional electron gas densities in the InsubyGasub1minusyAs channel. Electron sheet densities up to 2.75x10high12 cmminus2 have been obtained for x is equal 0.4 and y is equal 0.3 with appropriate doping. The structures have excellent Hall properties at room temperature and at 77 K. The critical interface between obtained for x equal 0.4 and y equal 0.3 with appropriate doping. The structures have excellent Hall properties at room temperature and at 77 K. The critical interface between the InGaAs channel layer and and the AlGaInP barrier layer has been improved by placing a thing AlGaAs interlayer (1.8 nm thick) between th ese two layers. This arrangement provides an abrupt interface between quantum well and interlayer and suppresses the interaction of the two-dimensional electron gas in the quantum well with the non-ideal interface between the interlayer and the AlGaInP barrier layer. Cathodoluminescence studies revealed that the mechanism of strain relaxation in these structures is distinctly different from the mechanism observed in AlGaAs/InGaAs/GaAs heterostuctures grown by molecular beam epitaxy.