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R. Gwilliam Nodus Accelerator Laboratory, Advanced Technology Institute, Surrey Ion Beam Centre, Guildford, Surrey GU2 7XH, United Kingdom (Received 16 July 2008; accepted 17 September 2008)

The solid-phase epitaxial growth kinetics of amorphized (011) Si with application of in-plane ½211 uniaxial stress to magnitude of 0.9  0.1 GPa were studied. Tensile stresses did not appreciably change the growth velocity compared with the stress-free case, whereas compression tended to retard the growth velocity to approximately one-half the stress-free value. The results are explained using a prior generalized atomistic model of stressed solid-solid phase transformations. In conjunction with prior observations of stressed solid-phase epitaxial growth of (001) Si, it is advanced that the activation volume tensor associated with ledge migration may be substrate orientation-dependent.

Stressed solid-phase epitaxial growth (SPEG) of Si amorphized via ion-implantation has become a topic of greater technological interest during the past several years due to the importance of SPEG in doping Si-based devices and the increasingly prevalent nature of stresses typically present during fabrication.1,2 The stressed-SPEG process has been studied in (001) Si under a variety of different stress states, including pure hydrostatic stress,3–7 uniaxial stress applied parallel to the growth direction,8 and inplane uniaxial stress applied perpendicular to the growth direction.9–11 Currently, (001) Si is used for both p- and n-type transistor in the vast majority of Si-based devices. However, there is growing interest in the use of hybrid orientation technology wafers that contain both (001)and (011)-oriented sections.12–14 In particular, the use of (011) Si is attractive for p-type transistors due to the inherently faster hole mobility and larger piezoresistive coefficients compared with (001) Si.15,16 SPEG of (011) Si has been studied far less compared with (001) Si. In fact, little else is known beyond the observations by Csepregi et al. who revealed (011)oriented SPEG to be much slower than (001)-oriented SPEG.17 Thus, the goal of this work is to study the stressed-SPEG process of (011) Si and determine how (011)-oriented stressed-SPEG differs from (001)oriented stressed-SPEG. In this study, a polished 50-mm-thick (011) Si wafer was Si+ implanted at 50, 100, and 200 keV to doses of 1  1015, 1  1015, and 3  1015 cm2 and subsequently As+ implanted at 300 keV to a dose of 1.8  1015 cm2. a)

Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2009.0056 J. Mater. Res., Vol. 24, No. 2, Feb 2009

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The wafer was subsequently cleaved along the in-plane ½211 direction into 0.2  1.8 cm2 strips (with 1 and 2 axes taken to be ½211 and ½111  crystal directions). Uniaxial stress up to magnitude of 0.9 GPa along ½2 11 (s11 ) was applied using the method presented elsewhere.18 By convention, positive (negative) values of s11 are tensile (compressive). The err