Low‐Temperature Selective Growth of Heavily Boron‐Doped Germanium Source/Drain Layers for Advanced pMOS Devices. Issue 3 (11th November 2019)

• Record Type: Journal Article
• Authors: Porret, Clement; Vohra, Anurag; Nakazaki, Nobuya; Hikavyy, Andriy; Douhard, Bastien; Meersschaut, Johan; Bogdanowicz, Janusz; Rosseel, Erik; Pourtois, Geoffrey; Langer, Robert; Loo, Roger
• Other Names: Tanaka Masaaki guestEditor.; Sugiyama Masakazu guestEditor.; Fujii Takuro guestEditor.; Ohya Shinobu guestEditor.
• Is Part Of: Physica status solidi. Volume 217:Issue 3(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-11-11
• Subjects: contact resistivity -- germanium pMOS -- low-temperature selective epitaxial growth -- source/drain materials; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.201900628
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : The peculiarities of heavily boron‐doped germanium, selectively grown at low temperature by means of a cyclic deposition and etch chemical vapor deposition process, are investigated through the analysis of the structural and electrical material properties. The incorporation of B in Ge can exceed 6 × 10 20 cm −3, close to a factor 100 above the solubility limit, without any significant degradation of the Ge:B crystalline quality, although high B‐doping induces an unwanted contraction of the Ge lattice. Micro‐Hall effect measurements and the multiring circular transmission line method are used to evaluate the active carrier concentrations and resistivities of Ti/Ge:B contacts. Even though the resistivity of as‐grown layers saturates for chemical B concentrations approaching 1 × 10 21 cm −3 and increases beyond that level, a contact resistivity below 3 × 10 −9 Ω cm 2 is obtained for the highest active doping concentration, showing that a compromise must be found to decrease the total contact resistance. Finally, first principles simulations are used to understand dopant deactivation mechanisms in the Ge:B system. In conclusion, the formation of boron‐interstitial clusters is most likely the cause for electrical performance degradation at high doping values. Abstract : The peculiarities of heavily boron‐doped germanium, selectively grown at low temperature by means of a cyclic deposition and etch chemical vapor deposition process, are investigated through the analysis of the structural and electrical material properties. The experimental studies are supported by first principles simulations which are used to understand dopant deactivation mechanisms in the Ge:B system.