AVS 53rd International Symposium
    Nanometer-scale Science and Technology Tuesday Sessions
       Session NS1-TuM

Paper NS1-TuM13
Reliable XPS Measurement of Sub nm SiO@sub 2@ Thickness by Determination of the Surface Normal

Tuesday, November 14, 2006, 12:00 pm, Room 2016

Session: Nanoscale Structures and Characterization II
Presenter: K.J. Kim, Korea Research Institute of Standards and Science
Authors: K.J. Kim, Korea Research Institute of Standards and Science
D.W. Moon, Korea Research Institute of Standards and Science
J.S. Jang, Chungbuk National University, Korea
H.J. Kang, Chungbuk National University, Korea
Correspondent: Click to Email
Recent international technology roadmap for semiconductor showed that the reliable measurement of ultra-thin gate oxide thickness below 1 nm is required for the next generation of semiconductor devices. X-ray photoelectron spectroscopy (XPS) is an ideal candidate. Recently, SiO@sub 2@ film thickness measured by various techniques was compared in the first pilot study in the surface analysis working group of CCQM. However, further studies are required to improve the traceability of the XPS measurement of SiO@sub 2@ thickness in the sub nm range. The diffraction effect of photoelectrons due to the crystallinity of the substrates has been regarded as one of the major issues in angle-resolved (AR) XPS analysis. The diffraction effect could be completely removed by using amorphous SiO@sub 2@ overlayers grown on an amorphous Si layer by ion beam sputter deposition. The film thickness could be measured without surface contamination by in-situ AR-XPS analysis. The thickness of the films was estimated by the growth rate determined from the high resolution-TEM. Without the diffraction effect and the surface contamination, the calibration curves of XPS measurement passed the origin.@footnote 1@ Additionally, the polar angle control is one of the critical factors for the accurate thickness measurement of SiO@sub 2@ films by AR-XPS. For the accurate control of the polar angle, the surface normal must be calibrated precisely. The accurate surface normal can be simply determined by minimizing the standard deviation of the thickness values estimated at different polar angles around the surface normal. With the new procedure, the surface normal could be determined accurately within 0.05@super o@. This study demonstrates that AR-XPS can provide reliable measurement of SiO@sub 2@ thickness down to sub nm range by accurate calibration of the surface normal. @FootnoteText@@footnote 1@K. J. Kim, K. T. Park and J. W. Lee, Thin Solid Films 500, 356-359 (2006).