A differential Hall effect measurement method with sub-nanometre resolution for active dopant concentration profiling in ultrathin doped Si1-x Ge x and Si layers

Richard Daubriac; Emmanuel Scheid; Hiba Rizk; Richard Monflier; Sylvain Joblot; Rémi Beneyton; Pablo Acosta Alba; Sébastien Kerdilès; Filadelfo Cristiano

doi:10.3762/bjnano.9.184

A differential Hall effect measurement method with sub-nanometre resolution for active dopant concentration profiling in ultrathin doped Si_1-_x Ge _x and Si layers

Beilstein J Nanotechnol. 2018 Jul 5:9:1926-1939. doi: 10.3762/bjnano.9.184. eCollection 2018.

Authors

Richard Daubriac¹, Emmanuel Scheid¹, Hiba Rizk¹, Richard Monflier¹, Sylvain Joblot², Rémi Beneyton², Pablo Acosta Alba³, Sébastien Kerdilès³, Filadelfo Cristiano¹

Affiliations

¹ LAAS-CNRS and Univ. of Toulouse.
² STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles, France.
³ CEA-LETI and Univ. of Grenoble, 17 rue des Martyrs, 38054 Grenoble, France.

Abstract

In this paper, we present an enhanced differential Hall effect measurement method (DHE) for ultrathin Si and SiGe layers for the investigation of dopant activation in the surface region with sub-nanometre resolution. In the case of SiGe, which constitutes the most challenging process, we show the reliability of the SC1 chemical solution (NH₄OH/H₂O₂/H₂O) with its slow etch rate, stoichiometry conservation and low roughness generation. The reliability of a complete DHE procedure, with an etching step as small as 0.5 nm, is demonstrated on a dedicated 20 nm thick SiGe test structure fabricated by CVD and uniformly doped in situ during growth. The developed method is finally applied to the investigation of dopant activation achieved by advanced annealing methods (including millisecond and nanosecond laser annealing) in two material systems: 6 nm thick SiGeOI and 11 nm thick SOI. In both cases, DHE is shown to be a uniquely sensitive characterisation technique for a detailed investigation of dopant activation in ultrashallow layers, providing sub-nanometre resolution for both dopant concentration and carrier mobility depth profiles.

Keywords: carrier mobility; contact resistance; differential Hall effect; dopant activation; fully depleted silicon on insulator (FDSOI); laser annealing; sub-nanometre resolution.