By Topic

Surface roughness generated by plasma etching processes of silicon

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $31
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Martin, M. ; Laboratoire des Technologies de la Microélectronique, CNRS-LTM, 17 rue des Martyrs, 38054 Grenoble Cedex, France ; Cunge, G.

Your organization might have access to this article on the publisher's site. To check, click on this link: 

The authors used atomic force microscopy to analyze the roughness generated on c-Si (100) surfaces when etched in high-density plasmas over a wide range of conditions (pressure, rf power) using SF6, CF4, Cl2, and HBr chemistries. The authors demonstrate unambiguously that high-density plasmas do not generate roughness during silicon etching; but on the contrary, they tend to smooth the existing surface roughness if already present. This is evidenced by analyzing the time evolution of the shape of self-organized silicon nanopillars (patterned on the Si wafer by using diblock copolymers as an etch mask). The 20-nm-high, 20-nm-wide pillars separated by 10 nm are rapidly smoothed by exposure to Cl2 and SF6 plasmas, thus restoring a flat silicon surface. In high-density plasmas, the local etch rate is generally limited by the availability of reactive radicals. In these conditions, the smoothing mechanism is due to the fact that the hills of a rough surface receive a higher flux of etchant radicals than the valleys. Finally, the authors show that the roughening of silicon surfaces in F-based plasma, often reported in the literature, is only due to the micromasking of silicon by AlFx particles originating from the sputtering of the (Al2O3) reactor walls. A high percentage of Al is indeed detected on the surface after etching in F-based plasmas. However, when the chamber walls are intentionally coated by a carbon layer prior to the silicon- - etching process, the F-based plasmas behave like the other etching chemistries investigated: they rapidly smooth any existing roughness.

Published in:

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures  (Volume:26 ,  Issue: 4 )