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An investigation of ion-bombarded and annealed <111 > surfaces of Ge by spectroscopic ellipsometry
A216 Surface Science 0 North-Holland
96 (1980) 275-293 Publishing Company
REALTIME AND SPECTROSCOPIC ELLIPSOMETRY OF FILM GROWTH: APPLICATION TO MULTILAYER SYSTEMS IN PLASMA AND CVD PROCESSING OF SEMICONDUCTORS
J .B. THEETEN Laboratoires d’Electronique Lime&Brkvannes, France Received
20 August
et de Physique Appliquke,
3, avenue Descartes, F-94450
1979
The use of ellipsometry in connection with vapor-phase epitaxy or plasma processing of semiconductors is reviewed. It is shown that the availability of this surface-sensitive, non-destructive, real-time method is a unique facility not only to monitor the kinetics of thin films deposition, but also to analyse the interface regions between distinct successive layers. In the case of rough interfaces, real-time ellipsometry is the only possible technique for detecting three-dimensional growth (a-Si nuclei on SisN4, Ga droplets on GaAs MBE layers). For more complex structures (for instance in the case when more than one layer changes at a time during the process), a complementary method is shown to be variable-energy and variable-angle-ofincidence ellipsometry. The possibilities and limitations of this spectroscopic ellipsometer are discussed on oxide/GaAs, SiOz/Si, as well as hypothetical interfaces.
Surface Science 0 North-Holland
96 (1980) 294-306 Publishing Company
AN INVESTIGATION
OF ION-BOMBARDED
AND ANNEALED (Ill
)
SURFACES OF Ge BY SPECTROSCOPIC ELLIPSOMETRY
D.E. ASPNES and A.A. STUDNA Bell Laboratories, Murray Hill, NJ 07974, Received
20 August
USA
1979
Ion-bombarded and annealed (111) Ge surfaces, maintained in ultrahigh vacuum and characterized by standard LEED and Auger surface analysis techniques, are examined by spectroscopic ellipsometry over the energy range 1.5-6.0 eV. The bombardment and annealing process is found to yield highly reproducible ellipsometric spectra, with run-to-run and sample-tosample variations of the order of 0.2% in the peak value of ~2. Accurate dielectric function spectra are obtained for c6e and for the amorphized overlayer formed by ion bombardment. The latter is shown to be 6 +_2% more dense than uhv-evaporated material, independent of bombarding species. The damage depth exceeds significantly the projected range parameters of the nuclear limit of the Lindhard-Scharff-Schidtt theory for both Ne and Ar ions, although the 15”” power law dependence on the ion energy is observed. Finally, the presence of -4 A of amorphous overlayer detected optically on a surface showing a 1 X 1 LEED pattern indicates reconstruction does not proceed uniformly, but by patches.
96 (1980) 275-293 Publishing Company
REALTIME AND SPECTROSCOPIC ELLIPSOMETRY OF FILM GROWTH: APPLICATION TO MULTILAYER SYSTEMS IN PLASMA AND CVD PROCESSING OF SEMICONDUCTORS
J .B. THEETEN Laboratoires d’Electronique Lime&Brkvannes, France Received
20 August
et de Physique Appliquke,
3, avenue Descartes, F-94450
1979
The use of ellipsometry in connection with vapor-phase epitaxy or plasma processing of semiconductors is reviewed. It is shown that the availability of this surface-sensitive, non-destructive, real-time method is a unique facility not only to monitor the kinetics of thin films deposition, but also to analyse the interface regions between distinct successive layers. In the case of rough interfaces, real-time ellipsometry is the only possible technique for detecting three-dimensional growth (a-Si nuclei on SisN4, Ga droplets on GaAs MBE layers). For more complex structures (for instance in the case when more than one layer changes at a time during the process), a complementary method is shown to be variable-energy and variable-angle-ofincidence ellipsometry. The possibilities and limitations of this spectroscopic ellipsometer are discussed on oxide/GaAs, SiOz/Si, as well as hypothetical interfaces.
Surface Science 0 North-Holland
96 (1980) 294-306 Publishing Company
AN INVESTIGATION
OF ION-BOMBARDED
AND ANNEALED (Ill
)
SURFACES OF Ge BY SPECTROSCOPIC ELLIPSOMETRY
D.E. ASPNES and A.A. STUDNA Bell Laboratories, Murray Hill, NJ 07974, Received
20 August
USA
1979
Ion-bombarded and annealed (111) Ge surfaces, maintained in ultrahigh vacuum and characterized by standard LEED and Auger surface analysis techniques, are examined by spectroscopic ellipsometry over the energy range 1.5-6.0 eV. The bombardment and annealing process is found to yield highly reproducible ellipsometric spectra, with run-to-run and sample-tosample variations of the order of 0.2% in the peak value of ~2. Accurate dielectric function spectra are obtained for c6e and for the amorphized overlayer formed by ion bombardment. The latter is shown to be 6 +_2% more dense than uhv-evaporated material, independent of bombarding species. The damage depth exceeds significantly the projected range parameters of the nuclear limit of the Lindhard-Scharff-Schidtt theory for both Ne and Ar ions, although the 15”” power law dependence on the ion energy is observed. Finally, the presence of -4 A of amorphous overlayer detected optically on a surface showing a 1 X 1 LEED pattern indicates reconstruction does not proceed uniformly, but by patches.