Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 44: Poster Session I

HL 44.45: Poster

Tuesday, March 15, 2011, 18:00–21:00, P3

Development of porous structures in GaSb by ion irradiation — •Tobias Steinbach, Carolin C. Jacobi, and Werner Wesch — Institute of Solid State Physics, Friedrich Schiller University Jena

Ion irradiation of GaSb causes not only defect formation but also leads to the formation of a porous structure. To study the behaviour of this structural modification, GaSb was irradiated with 6 MeV I and two different irradiation procedures: (i) continuous irradiation of samples followed by surface profilometry analysis in air, i.e. step height measurements, and (ii) stepwise irradiation of samples with measurements of the step height in air between subsequent irradiations. Samples irradiated continuously, show a moderate increase of the step height with increasing ion fluence (up to 1.5 x 10¹⁴ cm⁻²) followed by a much steeper increase for higher fluences up to a step height of 32 µm. This swelling is induced by the formation of voids, and the two different slopes can be explained by a change from isolated voids to a rod like structure (SEM investigations). For samples irradiated according to procedure (ii), the step height shows the same behaviour up to 1.5 x 10¹⁴ cm⁻² but then decreases with further irradiation. The latter effect is caused by an orientation of the rod like structure perpendicular to the ion beam and occurs only if the sample was taken out of the vacuum chamber and then irradiated once more. We investigated e.g. the influence of gas, oxygen, time and pressure but the reason for the change of the behaviour of GaSb, which leads to this effect, is still an open question.