OPTIMIZATION OF MODULATION-DOPED GA1-XINXAS INP HETEROSTRUCTURES TOWARDS EXTREMELY HIGH MOBILITIES/

This paper presents a study of the electrical and structural propertie s of inverted modulation-doped GaInAs/InP heterostructures grown by lo w-pressure metalorganic vapor phase epitaxy. First, the thickness of t he GaInAs layer was optimized in lattice-matched samples to find the s mallest thickness in which high Hall mobility is observed. Next, in a section closest to the InP the In content was varied. A steady increas e of mobility with indium composition was observed. A maximum of 450 0 00 and 15 500 cm2/V s was obtained for a 10-nm-thick Ga1-xInxAs layer with x = 0.77 at 6 and 300 K, respectively. Channels with higher indiu m content exceed the critical thickness and mobility drops off sharply . The decreasing mobility correlates with the formation of misfit disl ocations at the interface indicating increasing scattering processes o f the GaInAs layer.