Chemical vapor deposition of Si:C and Si:C:P films—Evaluation of material quality as a function of C content, carrier gas and doping Sathish Kumar Dhayalan a,b,n , Roger Loo a , Andriy Hikavyy a , Erik Rosseel a , Hugo Bender a , Olivier Richard a , Wilfried Vandervorst a,b a Imec, Kapeldreef 75, 3001 Leuven, Belgium b Dept of Physics, Instituut voor Kern en Stralingsfysica, K.U.Leuven, Celestijnenlaan 200D, 3001 Heverlee Belgium article info Article history: Received 10 February 2015 Received in revised form 7 May 2015 Accepted 19 May 2015 Communicated by: M. Tischler Available online 27 May 2015 Keywords: A2. Growth from vapor A2. CVD B2. Semiconducting Silicon compounds B3. Source drain stressors B3. FinFETS abstract Incorporation of source–drain stressors (S/D) for FinFETs to boost the channel mobility is a promising scaling approach. Typically SiGe:B S/D stressors are used for p FinFETs and Si:C:P S/D stressors for n FinFETs. The deposition of such Si:C:P S/D stressors requires a low thermal budget to freeze the C in substitutional sites and also to avoid problems associated with surface reflow of Si fins. In this work, we report the material properties of Si:C and Si:C:P epitaxial layers grown by chemical vapor deposition, in terms of their defectivity and C incorporation as a function of different process conditions. The undoped Si:C layers were found to be defect free for total C contents below 1%. Above this concentration defects were incorporated and the defect density increased with increasing C content. Abrupt epitaxial breakdown occurred beyond a total C content of 2.3% resulting in amorphous layers. P doping of Si:C layers brought down the resistivity and also thicker Si:C:P films underwent epitaxial breakdown. Additionally, the use of nitrogen instead of hydrogen as carrier gas resulted in an increase of the growth rate and substitutional C incorporation both by a factor of two, while the surface defect density reduced. & 2015 Elsevier B.V. All rights reserved. 1. Introduction The microelectronics industry has incorporated new technolo- gies and materials in every successive transistor node and has continued scaling in accordance with Moore's law [1]. We are currently in the 14 nm node, coinciding with the use of FinFETs that debuted in the 22 nm node [2]. Though there has been a considerable interest in introducing III-V MOSFETs (Metal oxide semiconductor field effect transistor) and/ or Ge MOSFETs, the introduction of these technologies before the 7 nm node seems to be rather difficult due to several technological challenges [3]. At present, improving the mobility (and hence the drive current) by the introduction of source-drain (S/D) stressors for FinFETs is more favorable. It is very well known from the case of planar MOSFETs that the use of SiGe(B) S/D stressors [4] for p type MOSFETs and Si: C:P S/D stressors [5] for n type MOSFETs enable enhanced device performance. Following a similar scheme of S/D stressors for FinFETs has been proven to boost their respective drive currents [6,7]. In this work, we focus on the epitaxial growth aspects of Si:C and Si:C:P films. This requires epitaxial growth at sufficiently low temperatures, in the range of o600 1C, in order to retain C in the substitutional lattice sites and to prevent surface reflow of thin Si fin structures [8]. At the afore mentioned temperatures, it is rather difficult to achieve a sufficiently high growth rate using conventional pre- cursor gases such as silane, dichlorosilane or trichlorosilane [9]. Higher order silanes such as disilane, trisilane, tetrasilane, neo- pentasilane, etc., can be used to grow epi layers at temperatures below 600 1C. Recently, there have been reports on the epitaxial deposition of Si:C using trisilane [10], neopentasilane [11] etc. The main problems associated with these gases are, i) their liquid phase which complicates their supply to the epi reactor, ii) the high cost especially for electronic grade quality [9,12], and iii) the concern for condensing into gas phase precipitates which may get incorporated into the growing epitaxial layer, leading to defect incorporation in the epitaxial layer [13]. In these aspects, the use of disilane, a gas phase precursor, is more beneficial and is also economic in comparison to other higher order silanes [12]. A couple of reports pertaining to the use of disilane to grow Si:C layers (in both gas-source Molecular Beam Epitaxy (MBE) as well as Chemical Vapor Deposition (CVD)), are already available [12–19]. Recently, Hartmann et al. [19] have demonstrated a selective process for Si:C and Si:C:P deposition using disilane. Their study mainly focused upon different processing aspects of the epilayer growth. The effect of nitrogen as carrier gas for the CVD of Si:C and Si:C:P films has not yet been dealt with. In the Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jcrysgro Journal of Crystal Growth http://dx.doi.org/10.1016/j.jcrysgro.2015.05.019 0022-0248/& 2015 Elsevier B.V. All rights reserved. n Corresponding author at: Imec, Kapeldreef 75, 3001, Leuven, Belgium. E-mail address: sathish.kumar.dhayalan@imec.be (S.K. Dhayalan). Journal of Crystal Growth 426 (2015) 75–81