{"id":1884,"date":"2010-07-13T14:42:15","date_gmt":"2010-07-13T18:42:15","guid":{"rendered":"https:\/\/wpmu2.mit.local\/?p=1884"},"modified":"2010-07-13T16:42:51","modified_gmt":"2010-07-13T20:42:51","slug":"sub-30-nm-patterning-of-au-on-gaas-substrates","status":"publish","type":"post","link":"https:\/\/wpmu2.mit.local\/sub-30-nm-patterning-of-au-on-gaas-substrates\/","title":{"rendered":"Sub-30-nm Patterning of Au on GaAs Substrates"},"content":{"rendered":"

In this work, we demonstrated the patterning of Au features on <111> B GaAs substrates by galvanic displacement and metal evaporation into sub-30-nm pores in a silicon oxide hard mask layer. Patterning of small Au features onto GaAs substrates is of particular interest due to their use as metal catalysts for GaAs and GaAs-alloy nanowire growth. Semiconducting nanowires have a variety of potential applications, such as field-effect transistors (FETs) [1<\/a>]<\/sup>, and their size-dependent properties have been exploited for a variety of optoelectronic devices [2<\/a>]<\/sup>. However, much work remains to create lithographically-templated nanowires for integration into future manufacturing processes.<\/p>\n

\"Figure<\/a>

Figure 1: (a) An array of GaAs nanowires grown epitaxially by MOCVD, catalyzed by patterned Au\/Cr metal features. (b) A 30-nm-diameter GaAs nanowire, with the metal catalyst clearly visible at the top of the nanowire.<\/p><\/div>\n

Gold in particular has shown promise in producing oriented, size-selected nanowires [3<\/a>]<\/sup>. This research significantly improves on the smallest lithographically-fabricated catalyst-particle size, while suppressing unwanted nanowires by controlling the migration of metal particles during the growth process and by preventing the self-catalysis of GaAs nanowires from the GaAs substrate.<\/p>\n

Samples were prepared using GaAs substrates with 30 nm of evaporated silicon oxide deposited on top. The samples were patterned by electron-beam lithography, using a PMMA resist, and developed via a cold development process [4<\/a>]<\/sup>. Pores were opened in the hard mask by HCF3<\/sub>\/CF4<\/sub> reactive-ion etching. After removal of the GaAs native oxide, metal catalyst nanoparticles were deposited into the pores by either electron-beam evaporation of Au, with a nominal thickness of 3 nm, or by galvanic displacement (GD) in a calibrated solution that also deposits 3 nm of Au.\u00a0 The GD solutions were prepared by dissolving hydrogen tetrachloroaurate(III) trihydrate (Alfa Aesar Co.) into deionized (DI) water. With either method, the sub-30-nm gold nanoparticles were fabricated.<\/p>\n

\r\nReferences
  1. J. Goldberger, A.I. Hochbaum, R. Fan, and P. Yang, \u201cSilicon vertically integrated nanowire field effect. Transistors,\u201d Nano Lett.<\/em>, vol. 6, p. 973, 2006. [↩<\/a>]<\/li>
  2. X. Duan, Y. Huang, Y. Cui, J. Wang, and C. M. Lieber, \u201cLogic gates and computation from assembled nanowire building blocks,\u201d Nature,<\/em> vol. 409, p. 66, 2001. [↩<\/a>]<\/li>
  3. P. Nguyen, H.T. Ng, and M. Meyyappan, \u201cGrowth of individual vertical germanium nanowires,\u201d Adv. Mater.,<\/em> vol. 17, p. 1773, 2005. [↩<\/a>]<\/li>
  4. B. Cord, C. Dames, and K.K. Berggren, \u201cRobust shadow-mask evaporation via lithographically controlled undercut\u201d J. Vac. Sci. Technol. B,<\/em> vol. 24, p. 3139, 2006. [↩<\/a>]<\/li><\/ol><\/div>","protected":false},"excerpt":{"rendered":"

    In this work, we demonstrated the patterning of Au features on <111> B GaAs substrates by galvanic displacement and metal…<\/p>\n<\/div>","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[11],"tags":[4208,41],"_links":{"self":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts\/1884"}],"collection":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/comments?post=1884"}],"version-history":[{"count":3,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts\/1884\/revisions"}],"predecessor-version":[{"id":1952,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts\/1884\/revisions\/1952"}],"wp:attachment":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/media?parent=1884"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/categories?post=1884"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/tags?post=1884"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}