Distribution and segregation of arsenic at the SiO2 /Si interface

Journal Article · Tue Jan 01 04:00:00 EST 2008 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2956700· OSTI ID:1050932

Steen, Christian ^[1]; Martinez-Limia, A ^[2]; Pichler, Peter ^[3]; Ryssel, Heiner ^[2]; Paul, S ^[4]; Pei, L ^[5]; Duscher, G. ^[6]; Severac, F ^[7]; Cristiano, F ^[7]; Windl, Wolfgang ^[8]

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1. Chair of Electron Devices, University of Erlangen-Nuremberg, Cauerstrasse 6, 91058 Erlangen,
2. Fraunhofer Institute of Integrated Systems and Device Technology, Schottkystrasse 10, 91058 Erlangen
3. Fraunhofer-Institute, Freiburg, Germany
4. Mattson Thermal Products GmbH, Daimlerstrasse 10, 89160 Dornstadt, Germany
5. Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC
6. University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL)
7. LAAS-CNRS, University of Toulouse, 7, avenue du Colonel Roche, 31077, Toulouse, France
8. Ohio State University

The segregation and pile-up of arsenic atoms at the Si/SiO2 interface in steady state was investigated in detail by a combination of gracing incidence x-ray fluorescence spectroscopy GI-XRF measurements, electrical measurements, etching on the nanometer scale, and measurements of the step heights by interferometry. Using GI-XRF measurements and removal of the highly doped segregation layer by a sensitive etching process it was possible to distinguish clearly between the piled-up atoms and the arsenic atoms in the bulk over a large range of implantation doses, from 31012 to 11016 cm 2. The samples were annealed at different temperatures from 900 C to 1200 C for time periods long enough to make sure that the segregation reflects an equilibrium state. With additional step height measurements at line-space structures, the thickness of the layer with the piled-up arsenic and the shape of the segregation profile was determined. Electrical measurements indicated that the segregated arsenic atoms are deep donors with an electrical activity that increases eventually to full electrical activation for high sheet concentrations of the segregated atoms. The measured data can be modeled as a steady state of neutral arsenic atoms in the segregation layer with positively charged substitutional arsenic atoms and free electrons. For the highest concentration, a saturation of the sheet concentration of segregated arsenic atoms was observed that correlates with the increase in electrical activation. For the use in process simulation programs, a three-phase segregation model was adapted and calibrated.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1050932
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 2 Vol. 104; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ARSENIC
ATOMS
DISTRIBUTION
ELECTRONS
ETCHING
FLUORESCENCE SPECTROSCOPY
INTERFEROMETRY
REMOVAL
SATURATION
SEGREGATION
SHAPE
SIMULATION
THICKNESS