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Strain Relaxation in Patterned Strained Silicon Directly on Insulator Structures



R Z. Lei, W Tsai, I Aberg, T B. O'Reilly, J L. Hoyt, D A. Antoniadis, H I. Smith, Albert J. Paul, Martin L. Green, J Li, R Hull


Strain relaxation is studied in Strained Silicon Directly on Insulator (SSDOI) substrates patterned with nano-scale features. Using interference lithography, biaxially-strained SSDOI substrates with 30 nm-thick strained Si on insulator films were patterned into grating structures with 90 nm-wide stripes, and arrays of 80 nm x 170 nm pillars. The strain profiles of these patterned structures were examined by Raman spectroscopy using UV laser excitation (363 nm wavelength). Use of UV excitation ensures that the Raman signal originates from the top 30 nm-thick Si film. Raman analysis of the SSDOI gratings indicates strain relaxation in the 90 nm-wide stripes, compared to the strain measured in un-patterned portions of the SSDOI wafer. Three-dimensional finite-element modeling of the stress distributions in the grading structures predicts that 95% of the strain is maintained in the direction along the length of the stripes. These simulations are used to decouple the strain components along the width and length of the SSDOI grating structure, inferred from Raman measurements. The results are consistent with substantial stress relaxation across the width of the stripes and very little stress relaxation along the length of the stripes.
Applied Physics Letters


microelectronics, Raman spectroscopy, silicon wafers, strained silicon


Lei, R. , Tsai, W. , Aberg, I. , O'Reilly, T. , Hoyt, J. , Antoniadis, D. , Smith, H. , Paul, A. , Green, M. , Li, J. and Hull, R. (2005), Strain Relaxation in Patterned Strained Silicon Directly on Insulator Structures, Applied Physics Letters (Accessed April 14, 2024)
Created December 18, 2005, Updated October 12, 2021