{"id":3189,"date":"2011-06-28T19:05:46","date_gmt":"2011-06-28T19:05:46","guid":{"rendered":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/?p=3189"},"modified":"2011-07-19T20:17:17","modified_gmt":"2011-07-19T20:17:17","slug":"uniaxial-strained-ge-for-non-planar-p-mosfets","status":"publish","type":"post","link":"https:\/\/mtlsites.mit.edu\/annual_reports\/2011\/uniaxial-strained-ge-for-non-planar-p-mosfets\/","title":{"rendered":"Uniaxial Strained Ge for Non-planar p-MOSFETs"},"content":{"rendered":"

Uniaxial strained Ge \u201cnanobars\u201d are of interest for future sub-10-nm gate length p-MOSFETs because of the excellent electrostatic control afforded by the non-planar device geometry and the potential for high hole velocity in the uniaxial strained Ge.\u00a0 This work investigates the fabrication technology for uniaxial strained Ge structures.\u00a0 The basic approach is to pattern a biaxially strained Ge epitaxial layer grown on a relaxed SiGe substrate into a narrow nanobar.\u00a0 The free surfaces of the nanobar sidewalls allow for the elastic relaxation of the lattice strain in the direction transverse to the bar, while maintaining the strain in the longitudinal direction [1<\/a>] <\/sup>.\u00a0\u00a0 Figure 1 shows a simulation of this effect, for 11-nm-thick strained Ge grown on relaxed SiGe after patterning into a 26-nm-wide nanobar. Figure 2 shows experimental results illustrating this concept.\u00a0 Raman spectroscopy was used to measure the amount of strain in the Ge nanobars for various widths that were patterned by e-beam lithography.\u00a0 The Raman data is consistent with lateral relaxation and shows that the strain approaches the uniaxial limit for ~ 20-nm-wide bars.\u00a0 These results are promising for the fabrication of future tri-gate type p-MOSFETs with improved transport properties.<\/p>\n\n\t\t