Electrical characteristics of Ar‐ion sputter induced defects in epitaxially grown n‐GaAs
ABSTRACT Epitaxially grown n‐type GaAs was sputtered by bombarding it with Ar ions at energies of between 0.5 and 5 keV at a dose of 1013 ions/cm2. The fabrication of Au Schottky barrier contacts followed directly after the sputtering. The electrical characteristics of the the sputter induced defects were studied using deep‐level transient spectroscopy (DLTS). Several defects with discrete defect levels ranging from 0.05–0.70 eV below the conduction band, as well as defects with continuously distributed energies in the conduction band, were introduced during sputtering. Concentration depth profiling revealed that whereas some defects are located very close to the interface, others were detected several microns below the interface. The depth of some of these deep lying defects increased with sputter voltage. A possible explanation of the reduction in EL2 DLTS signal previously observed after sputtering is shown to be the sputter induced barrier height lowering.
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ABSTRACT: In this study the influence of low energy hydrocarbon ion irradiation at a glancing angle on electronic properties of the GaAs surface and Al–GaAs interface was investigated. The formation of a thin carbon enriched multiphase layer on the GaAs surface was observed. Despite this, reduction of the low-frequency noise, (especially at low temperatures), and effective barrier height of Schottky contacts were achieved at irradiation doses ⩾1015 ion/cm2. The obtained results are explained by the homogenization of the current flow through the Al–GaAs Schottky contact interface layer.Solid-State Electronics. 01/2003;
- Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures. 01/2002; 20(2):566-569.