Vacuum 78 (2005) 353–359 Peculiarities of the track formation in InP and GaAs crystals F.F. Komarov a,Ã , L.A. Vlasukova a , V.N. Yuvchenko a , T.V. Petlitzkaya b , P. Zukowski c a Belarussian State University, F. Skorina Ave. 4, 220050 Minsk, Belarus b Research and Design Company ‘‘Belmicrosystems’’, Korzenevsky Str. 12, 220108 Minsk, Belarus c Lublin Technical University, Nadbystrzycka Str. 38A, 20-618 Lublin, Poland Abstract Track formation processes in InP and GaAs crystals irradiated with swift Bi and U ions to fluences in the range 5  10 10 –1  10 12 cm 2 have been investigated by means of selective chemical etching (SCE), atomic force microscopy (AFM) and computer simulation. SCE data on the InP crystals show the formation of the two-layer system of tracks differing by the matrix disorder degree under the Bi ion irradiation. Transition from an individual track embedded in an unchanged solid (single tracks) to a modified solid (consisting of partial overlapping tracks) is observed at the fluence of 1  10 12 Bi/cm 2 . Ion tracks in GaAs samples irradiated with U and Bi ions to the fluence of 5  10 10 cm 2 were registered by means of AFM and SCE. The density of the tracks obtained from AFM data coincides well with the irradiation fluence. Fluence growth up to 1  10 12 cm 2 leads to the annealing of the tracks formed in GaAs on the early stages of irradiation. The results of the computer simulation of the track formation processes in InP and GaAs crystals are also presented. Simulation was based on the modified thermal spike model, including thermal dependencies of thermophysical properties and containing no free parameters. Calculated diameters of molten regions near the surface of the crystal are 20.6 and 17.4 nm for InP and GaAs crystals, respectively, irradiated with 710 MeV Bi ions. The comparison of the calculation results with the experimental data has been made. r 2005 Elsevier Ltd. All rights reserved. Keywords: InP and GaAs crystals; Heavy ion irradiation; Tracks; Selective chemical etching; Atomic force microscopy; Modified thermal spike model 1. Introduction Swift heavy ion irradiation is a promising technique for nanostructuring of solids. The out- standing characteristic of high-energy ion irradia- tion is the high level of electronic excitations arising from ion inelastic collisions in solids. ARTICLE IN PRESS www.elsevier.com/locate/vacuum 0042-207X/$-see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.vacuum.2005.01.110 Ã Corresponding author. Institute of Applied Physics Pro- blems, Belarussian State University, Kurchatova Street 7, Minsk 220064, Byelorussia. Tel.: +375172124833; fax: +375172780417. E-mail address: komarovf@bsu.by (F.F. Komarov).