Unexpected properties of the inductively coupled plasma induced defect in germanium

Loading...
Thumbnail Image

Authors

Coelho, Sergio M.M.
Auret, Francois Danie
Janse van Rensburg, Pieter Johan
Nel, Jacqueline Margot

Journal Title

Journal ISSN

Volume Title

Publisher

Elsevier

Abstract

Inductively coupled plasma (ICP) etching of germanium introduces a single defect, the E0.31 electron trap, for a large range of argon partial pressures from 4 × 10-3 to 6.5 × 10-4mbar that correspond to ion energies of 8 to 60 eV. Ge of three crystallographic orientations, (100), (110) and (111), treated with 20 and 60 eV ICP had defect concentration profiles that were similar in appearance, with a maximum concentration of 1014 cm-3 extending more than a μm into the material, approximately three orders of magnitude deeper than what TRIM simulations predicted. All profiles were measured using Laplace deep level transient spectroscopy (L-DLTS), a technique that is sensitive to defect concentrations as low as 1011 cm-3. Isochronal annealing of samples showed concentration curves broadening after a 400 K anneal and decreasing to the 1013 cm-3 level after a 450 K anneal. Unannealed samples measured after a year exhibited similar decreases in defect concentration without broadening of their profiles. A 550 K anneal lowered the defect concentration to levels below the L-DLTS detection limit. Thereafter additional plasma treatment of the surface failed to reintroduce this defect indicating that the structure required for the formation of E0.31 was no longer present in the region under observation.

Description

Keywords

Germanium, Defect, Anneal, Diffusion, Inductively coupled plasma (ICP), Laplace deep level transient spectroscopy (L-DLTS), Deep level transient spectroscopy (DLTS)

Sustainable Development Goals

Citation

Coelho, SMM, Auret, FD, Janse van Rensburg, PJ & Nel, JM 2014, 'Unexpected properties of the inductively coupled plasma induced defect in germanium', Physica B: Condensed Matter, vol. 439, pp. 97-100.