Publication Date:
2014-11-05
Description:
Surface condition before an insulator deposition is the key issue for the preparation of reliable GaAs-based metal-oxide-semiconductor (MOS) devices. This study presents the preparation and properties of InGaAs/GaAs MOS structures with a double-layer insulator consisting of an oxygen-plasma oxide covered by Al 2 O 3 . The structures were oxidized during 75 s and 150 s. Static measurements yielded a saturation drain current of ∼250 mA/mm at V G = 1 V. Capacitance measurements showed improved performance in the depletion region compared with the structures without the double-layer insulator. Trapping effects were investigated by conductance vs. frequency measurements. The trap state density was in order of 10 11 cm −2 ·eV −1 with a continuous decrease with increased trap energy. The carrier mobility evaluation showed peak values of 3950 cm 2 /V·s for 75 s and 4570 cm 2 /V·s for 150 s oxidation times with the sheet charge density ≅2 × 10 12 cm −2 . The results demonstrate great potential of the procedure that was used to prepare the GaAs-based MOS devices with oxidized GaAs surface covered with an Al 2 O 3 insulator.
Print ISSN:
0003-6951
Electronic ISSN:
1077-3118
Topics:
Physics
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