Influence of the plasma pretreatment of GaAs 100/ and Si 100/ surfaces on the optical and structural properties of Si N rGaAs 3 4 and a-SiGerSi interfaces

The formation of structurally and optically well-defined Si3N4rGaAs 100.interfaces is presented. A high reproducibility both with highly doped and semi-insulating GaAs crystals was achieved. The thickness of the insulator prepared by rf sputtering under high-vacuum conditions was 100 nm. The general applicability of the plasma treatment used is documented on a plasma CVD grown a-SiGe:Hr Si 100. interface, which exhibits similar structural properties. The thickness of the amorphous layer was 1 mm. The surface pretreatment was done by hydrogen andror argon capacitively coupled plasma. The most significant result was obtained by X-ray diffraction at grazing incidence XRDGI.on the plasma pretreated samples on both types of interfaces or semiconductors. The diffraction pattern at grazing angle of 1.58 is dominated by a single extremely sharp 311 reflection corresponding to the coherence length of ;300 nm. The intensity of this reflection is by two orders of magnitude lower on the reference sample distributed by commercial producers. q2000 Elsevier Science B.V. All rights reserved.