A benchmark of co-flow and cyclic deposition/etch approaches for the selective epitaxial growth of tensile-strained Si:P

• Published in: Semiconductor science and technology Vol. 32; no. 10; pp. 104003 - 104011
• Main Authors: Hartmann, J M, Veillerot, M, Prévitali, B
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.10.2017
• Subjects: atmospheric pressure-chemical vapor deposition; cyclic deposition/etch; doping and selectivity; growth kinetics; Si:P raised sources and drains; tensile strain
• ISSN: 0268-1242; 1361-6641
• DOI: 10.1088/1361-6641/aa82d4

We have compared co-flow and cyclic deposition/etch processes for the selective epitaxial growth of Si:P layers. High growth rates, relatively low resistivities and significant amounts of tensile strain (up to 10 nm min−1, 0.55 mOhm cm and a strain equivalent to 1.06% of substitutional C in Si:C layers) were obtained at 700 °C, 760 Torr with a co-flow approach and a SiH2Cl2 + PH3 + HCl chemistry. This approach was successfully used to thicken the sources and drains regions of n-type fin-shaped Field Effect Transistors. Meanwhile, the (Si2H6 + PH3/HCl + GeH4) CDE process evaluated yielded at 600 °C, 80 Torr even lower resistivities (0.4 mOhm cm, typically), at the cost however of the tensile strain which was lost due to (i) the incorporation of Ge atoms (1.5%, typically) into the lattice during the selective etch steps and (ii) a reduction by a factor of two of the P atomic concentration in CDE layers compared to that in layers grown in a single step (5 × 1020 cm−3 compared to 1021 cm−3).