Materials Science and Engineering B 114–115 (2004) 251–254 Implant damage and redistribution of indium in indium-implanted thin silicon-on-insulator Peng Chen a , Zhenghua An b , Ming Zhu a,b , Ricky K.Y. Fu a , Paul K. Chu a,∗ , Neil Montgomery c , Sukanta Biswas c a Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong b State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, 200050 Shanghai, China c Cascade Scientific, Brunel Science Park, Uxbridge, Middlesex UB83PH, UK Abstract The indium implant damage and diffusion behavior in thin silicon-on-insulator (SOI) with a 200 nm top silicon layer were studied for different implantation energies and doses. Rutherford backscattering spectrometry in the channeling mode (RBS/C) was used to characterize the implant damage before and after annealing. Secondary ion mass spectrometry (SIMS) was used to study the indium transient enhanced diffusion (TED) behavior in the top Si layer of the SOI structure. An anomalous redistribution of indium after relatively high energy (200 keV) and dose (1 × 10 14 cm -2 ) implantation was observed in both bulk Si and SOI substrates. However, there exist differences in these two substrates that are attributable to the more predominant out-diffusion of indium as well as the influence of the buried oxide layer in the SOI structure. © 2004 Elsevier B.V. All rights reserved. Keywords: Indium; Implant damage; Diffusion; SOI; SIMOX 1. Introduction As a heavy ion, indium has become a promising dopant to achieve ultra-shallow or steep retrograde channel profiles (SRCP) in advanced metal-oxide-semiconductor field-effect- transistors (MOSFETs) [1–4]. However, due to its heavy mass, implantation-induced damage is quite considerable even at relatively low doses typically used in channel dop- ing. Moreover, the poor electrical activation of indium in Si due to the high ionization energy [5] and low solid solubility [6] necessitate the implantation of a higher dose. The large amount of ion implantation induced damage will affect both indium diffusion during subsequent thermal processes and the electrical characteristics of the final devices. Transient enhanced diffusion (TED) of indium in Si has been observed and the magnitude is comparable to that of boron [6–9], and it poses one of the main challenges to form steep and shallow profiles. ∗ Corresponding author. Tel.: +852 2788 7724; fax: +852 2788 9549/7830. E-mail address: paul.chu@cityu.edu.hk (P.K. Chu). Silicon-on-insulator (SOI) substrates have many advan- tages over bulk silicon in high-speed, low-power devices [10–11] and indium implantation into SOI can further im- prove the device performance. Although much research has been devoted to indium implantation and diffusion in bulk Si, that on indium implantation into SOI is relatively scarce. In addition, although some dopants, such as boron and phosphorus have been shown to exhibit different diffusion behavior in SOI compared to bulk Si [12–14], detailed com- parison between the diffusion of indium in SOI and bulk sil- icon has not been carried out. In this work, the implantation induced damage and indium diffusion characteristics were studied. The SOI wafers used were separation by implanta- tion of oxygen (SIMOX) wafers that are commonly used for fully depleted metal-oxide-semiconductor field-effect tran- sistors (MOSFETs) [15]. We investigated systematically the indium ion implantation induced damage under different im- plant energies and doses. The indium diffusion behavior in the SOI structure, especially in the top Si layer, was also studied, and the results were compared to those obtained in bulk Si. The difference between the indium diffusion pro- files in SIMOX and bulk Si implanted at a relatively high 0921-5107/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.mseb.2004.07.031