ISSN:
0142-2421
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
The analytical conditions necessary for the accurate measurement of shallow As implant profiles in crystalline Si have been critically evaluated. It is shown that near-normal oxygen bombardment (θ = 2°) gives rise to a drive-in of the As peak toegether with an enlarged exponential tail due to segregation processes associated with SiO2 formation in the near-surface region. At θ = 45°, both effects are greatly reduced. Thus, for enhanced depth resolution, it is essential to use oblique bombardment with low probe energies. Silicon sputter yield variations in the pre-equilibrium region are shown to be much smaller with θ = 45° and the differential peak shift amounts to only 0.6 nm per keV O+ compared with 3.0 nm at θ = 2°. The oblique sputter conditions do, however, lead to an increase in the thickness (w) of the pre-equilibrium region together with a loss in analytical sensitvity. The use of an oxygen jet is shown to reduce w to about 1 nm but gives rise to ‘chemically induced’ profile tailing with low energy (5 keV) As implants. Systematic measurements with different probe energies (1 and 2 keV O2+) show that As implants down to 10 keV are reliably profiled with θ = 45°. Comparison of our As range data with published Rutherford backscattering spectrometry values shows good agreement for the standard deviation while the mean projected range shows a systematic difference of ≃ 10%.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/sia.740100704
