Scanning probe microscopy characterisation of masked low energy implanted nanometer structures Thomas Winzell a, * , Srinivasan Anand b , Ivan Maximov c , Eva-Lena Sarwe c , Mariusz Graczyk c , Lars Montelius c , Harry J. Whitlow a a Department of Nuclear Physics, Lund Institute of Technology, Box 118, S-221 00 Lund, Sweden b Laboratory of Semiconductor Materials, Department of Electronics, Electrum 229, Isafjordsgatan 22-26, S-164 40 Kista, Stockholm, Sweden c Division of Solid State Physics, Lund Institute of Technology, Box 118, S-221 00 Lund, Sweden Received 4 July 2000; received in revised form 15 August 2000 Abstract In order to fabricate and characterise nanometer structures, silicon wafers were implanted with masks ranging from several lm down to 200 nm in lateral dimensions. The masks were produced by an electron beam lithography, metal deposition and metal lift-o sequence. 10 keV 75 As  -ions were implanted to a ¯uence of 2:5  10 14 cm 2 to create nanometer-sized doped and undoped volumes. Characterisation of the ion-implanted patterns was carried out by etching away the metal masks and subsequently using atomic force microscopy (AFM) and scanning capacitance microscopy (SCM) images of the patterns. The simultaneous AFM and SCM measurements gave sharp contrasts between implanted and unimplanted regions, showing highly resistive swelled structures. The swelling also showed structure with a concave shape for implanted regions and a convex shape for unimplanted regions, which is most probably a result of damage evolution from the implantation. Ó 2001 Elsevier Science B.V. All rights reserved. PACS: 61.82.Fk; 07.79)v; 07.79.Lh; 34.50.)s Keywords: Low energy ion implantation; AFM; SCM; Nanometer structures 1. Introduction The increasing demand of smaller and smaller feature sizes of silicon devices has increased the requirements on the doping, mask fabrication and characterisation tools. Ion implantation is by far the most adopted doping tool today because of its natural ability to control all parameters of interest, e.g., depth (energy), ion ¯uence, ion species and doping rate. However, the shrinkage of feature dimensions down into the nanometer range in- duces several problems using ion implantation, e.g., ion channelling eects (especially for light elements such as boron [1±4]), lateral spread (lat- eral straggling) [5±7], and mask edge eects (for Nuclear Instruments and Methods in Physics Research B 173 (2001) 447±454 www.elsevier.nl/locate/nimb * Corresponding author. Tel.: +46-46-7682; fax: +46-46- 4709. E-mail address: thomas.winzell@nuclear.lu.se (T. Winzell). 0168-583X/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 0 0 ) 0 0 4 1 6 - X