Ž . Applied Surface Science 141 1999 333–338 AFM studies of hydrogen implanted silicon A. Pia˛tkowska a, ) , G. Gawlik b , J. Jagielski b a Warsaw Technical UniÕersity, Institute of Micromechanics and Photonics, 02-525 Warsaw, ul. Chodkiewicza 8, Poland b Institute of Electronic Materials Technology, 01-919 Warsaw, ul. Wolczynska 133, Poland ´ ´ Received 29 May 1998; accepted 31 July 1998 Abstract ² : The effects of hydrogen implantation on the surface microtopography of 100 silicon single crystals were analyzed by Ž . means of atomic force microscopy AFM technique. The main objective of the study was to get a new insight into the processes occurring during the early stages of hydrogen blister formation in SmartCut w technology used in Silicon-on-Insu- lator devices manufacturing. The results revealed that hydrogen blistering sets in at doses about 4 =10 16 H q rcm 2 by a 2 formation of small, few tens of nanometer high bubbles. The increase of the implantation dose results first in the growth of the bubbles up to few hundreds nm and then in the formation of the next generation of small hydrogen clusters. The detailed analysis of the SiO surface layer formed on the silicon crystals indicated the presence of small, few nm in size, hillock-like 2 structures which can be responsible for the difficulties in SiO –SiO face-to-face bonding. A possible use of implantation 2 2 induced microtopography changes in Microelectronics and Micromechanical Systems applications is also discussed. q 1999 Elsevier Science B.V. All rights reserved. PACS: 61.16.Ch; 46.30.Nz; 61.72.Tt; 68.35.Ct; 85.40.Ux Ž . Keywords: Atomic force microscopy AFM ; Ion implantation; Silicon technology 1. Introduction Ž . The silicon-on-insulator SOI technology is one of the modern semiconductor technologies allowing to extend the applications of silicon-based devices towards higher frequency range and lower power w x sources voltage 1–3 . The SOI concept is based on the formation of a thin, crystalline silicon layer on an insulating substrate. Among numerous methods of w wx SOI fabrication the SmartCut 4 concept seems to ) Corresponding author. Tel.: q48-22-660-8543; E-mail: kup_pia@mp.pw.edu.pl be of particular interest. This method consists in Ž face-to-face bonding of two silicon wafers, one of . them oxidized and implanted with hydrogen ions and thermal processing. During the annealing the planar defects created by hydrogen implantation ex- pand laterally leading to the delamination of a crys- talline silicon layer that remains bonded to the sur- face of the second wafer. The critical factors of this technique are: planar extension of the defect induced by hydrogen ions and low rugosity of the exfoliated surface. Consequently, a nanoscale method of sur- face microtopography is required for the characteri- zation of the occurring processes. The AFM tech- nique is thus perfectly suited for this application. 0169-4332r99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved. Ž . PII: S0169-4332 98 00520-0