Special Topics PHY 250
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This 17 page Class Notes was uploaded by Horace McClure on Tuesday September 8, 2015. The Class Notes belongs to PHY 250 at University of California - Davis taught by James Crutchfield in Fall. Since its upload, it has received 17 views. For similar materials see /class/191837/phy-250-university-of-california-davis in Physics 2 at University of California - Davis.
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Date Created: 09/08/15
DipPen Nanolithography IIAFM Ti kg f M 160 WrIlingdireclion A Moleculartranspari E I A 39 quotyatermeniscus 5 D g 0 5 10 c 80 39 I x 0 2 40 5 a C j 0 I I I I I 0 2 4 6 8 10 Tip speed391 slum C S Mirkin et al Science 283 661 1999 Science 286 523 1999 288 1808 2000 J J De Yoreo et al Nanoletters 2 109 2002 James J De Yoreo et al LLNL P11143883 255505 2002 Lithography 36 Liu UCD PhyZSOZ 2009 NanoFab IIF Step Growth Substrate modi cation to create steps patches etc Subsequent growth lead to isolated patterns Depends on how the steps are created Deposition on both grooves and ridges directional deposition grazing angle V groove Each patch 1 X l um Gadetsky et al JAP 79 5687 1996 Lithography 37 Liu UCD Phy2502 2009 NanoFab Step Growth2 material 1 a gt gt as deposited after annealing prepatterned substrate PdSilicide formation thin Ta surface layer 100 nm e 0 Hellwig et a1 APL 93 192501 2008 100 nm d Lithography 38 Liu UCD Phy2502 2009 NanoFab Step Growth3 V grooved substrates I 2 1 OD Fig 1 Schematic illustralion of the preparation process for Vgroove mlcrostruclured substrates i 1005iwafer with microsu39ipe panem of alternating 0 and Si regions ii Wet etching with KOH solution iii Vgroove vgraovad substrate Shinjo amp Ono JMMM 177181 3136 1998 CuIrent Perpendicular to the Plane CPP GlVlR 2007 Physics Nobel Prize CuIrent In the mane CI ngh Reslstance LOW Res1stance Lithography a 39 Liu UCD Phy250 2 2009 NanoFab Step Growth4 Miscut substrate Thickness limited by step thickness Low angle deposition FIG 3 a Schematic rspresemahon orthc two cpttttxtai relationships Em and ERZ b High resolution image or the themIsittcon interface of IS A t cws direction 1710 St direction 39Ihe dark lines shew he bnenm on ol 1 1 1 memnic planes In the cenira pan 1 sample exhibits the ERZ tciattohshtp Sussiau et a APL 69 857 1996 Lithography 40 Liu UCD Phy2502 2009 NanoFab Step Growth5 Miscut substrate 24 av Lin et a1 APL 78 829 2001 Lithography 41 Liu UCD PhyZSOZ 2009 NanoFab Step Growth6 Easy Hard Annealed NaCl substrates E 05 1 C m 5 E r l SlO de osition 0 Fe ux A g as Q quot39 a 110 g M E l 001 5 D 39 20v 5 3510 U 05 Nagl110 g on 11 110 su SHE S s I 39 quot s 22 D FIG 1 Schematic deplclion of the preparation of self quot 39 u assembling uanomclepdlamslsr arrays of Fe islands Sc text 9 0 09gt F E d We FIG 2 Mngnclic and smlcmral properlies oflincar army of Fe puvlicles ornominal dlnmeler D33 nm top row 51 nm middle row and 67 nm bouan row SMOKE hysteresls loops lllken Sugawara amp Scheinfeim PRB 56 8499 1997 along Ole easy dlreolioll alnng lhe win lien most column and perpcndlcular m lllc wlre the hard dllccuon cenler column are shown w symbols The Manic Larln mlcmmsgnc Ius laled llysleresls lamps are plotted whh solid lines ADFrSTEM lm lges oreacll linear array are shown right most column for each nominal particle size Lithography 42 Liu UCD Phy2502 2009 NaIloFab r E a lluu Lithography IIG Nanoimprint Master mold Deform resist Etching Fast mold 1 Imprint Presslllold reslsl subsxrace iemnvs Mold 2 Pattem Tiansfcr ms V m 1 Schemalic ofnanmmpnnl Inhogmphy praccss39 a Imprinlmg using 1 mold us create 1 thickness comm m a renst and 1 pm m tmnsfcr usmg amsouapxc ctchmg w cmovc residue mm in me cumplcsscd mas Liu UCD Phyzsoz 2009 NanoFab NanoimprintZ a v o a 1 o a 3 0 4 90aogauv org 0 o amas 35K i s k39 i h x k i bnn FIG 2 IBM micrograph of a 5102 mold Mm a m mimmum dimmer Fm 3 SEM micrograph ofa op wow nf O nm deep holes Implimcd mm FIG 4 SFM mmmvh of a we view of 10 nm minimum dmmmer mr pillars mm a 40 nm period which are 60 um mll a cr being usud 12 mm PMMA which have n 39 v 39 k 39 ml PMMA and a hfwn process Chou et a J Vac Sci Technol B 15 2897 1997 Lithography 44 Liu UCD Phy2502 2009 NanoFab N anoimprint3 me stamp me repnm Transler pakem Evaparme w ebeam hy phum by phmo hy reacuvemn Magneuc mhogvaphy polymenzamn polymemuun alchmg Wm McClellandHart Rettner Best cmquot Tenis APL 81 1483 2002 Lithography 45 LmUCD Pkg25072 2009 NanoFab Nanoimprint 4 Laser Assisted Direct Imprint a Contact mould and 0 Silicon embossing substrate t O O lt t lt 250 ns Quartz It 1 i Figure 1 Schematic of laserassisted direct imprint LADI of nanostructures in silicon a A quartz Si mould is brought into contact with the silicon substrate A force presses the mould against the substrate b A single XeCl 308 11111 wavelength excimer laser pulse 20 HIH pulse width melts a thin surface layer of Si c The molten silicon is embossed 1 Silicon solidification b Excimer laser 1 gt irradiation t gt 0 ihv while the silicon is in the liquid phase ii The silicon rapidly solidi es e The mould and silicon substrate e Mou39d and SUbStrate are separated leaving a negative pro le ofthe mould Monen SI separation patterned in the silicon f The re ectivity of a HeNe laser beam from the silicon surface versus the time when the silicon surface is irradiated b a single XeCl 20 ns pulse duration Molten Si becoming a metal u 308 mm laser pulse with 16 m cm392 uence and f 060 gives a higher re ectivity The measured re ectivity 2 shows the silicon in liquid state for about 220 ns g 040 E 020 Chou Keimel and Gu Nature 417 835 2002 039 CC 0 O 50 100 150 200 250 300 350 400 Time ns Lithography 46 Liu UCD Phy2502 2009 NanoFab Nanoimprint S Laser Assisted Direct Imprint Figure 3 SEM image of the crosssection of samples patterned using LADI aA quartz mould b Imprinted patterns in silicon The imprinted silicon grating is 140 mm wide 110 mm deep and has a 300 nm period aninverse ofthe mould We note that the 10 mm wide and 15 mm tall silicon lines at each top comer of the silicon grating are the inverted replicas of the small notches on the mould the notches were caused by the reactive ion etching trenching during mould fabrication This indicates the sub10nm resolution of the LADI process These images are representative only In fact the Si structure in the image was probably not imprinted by the structure shown in the mould image Chou Keimel and Gu Nature 417 835 2002 Lithography 47 Liu UCD Phy250 2 2009 NanoFab IIH Shadow Mask Alumina Mask J Liu et a1 APL 81 4434 2002 Liftoff F Thickness hole size 6 NanOdOtS Lithography 48 Liu UCD Phy2502 2009 NanoFab a b c d Fig 3 Imagns n m may of bime alhc dun a An and Ag 3 SEM image v n v a h and blue mspcchvely Masuda Yasui Nishio Adv Mater 12 1031 2000 Lithography 49 Liu UCD Phy2502 2009 NanoFab F1 cal ions FIG 2 Correlation of Ni island nucleation with Au recon struction a Typical reconstructed section of large terrace on clean Aul I Light zigzagging bands are 0r2Ahigh ridges where atoms are near bridge sites quotElbowsquot in ridges lie on two nearly horizontal domain boundaries The lower boundary contains pinched elbows the upper one quotbulgedquot elbows V5 39 20 V b Completed nucleation and polygo nal shape of Ni islands at 014 ML V Or l V deposition rate Oil MLminr Of thousands of islands observed in dozens III SelfAssembly Nucleation1 N1 dots on Au 111 a E ridges 99 form at these elbow sites In b and c a non 200A linear gray scale is used to make ridges visible c Nucleation of Ni islands at elbows at 000l Three islands are seen on each of two domain boundaries of the herringbone pattern c d 22X running diagonally from upper left to lower right V ll yx V deposition rate 005 MLminr d Sketch of herringbone pattern and nucleation sites Two pairs of ridges are shown as dark bands Arrows on the upper pair show directions of Burgers vectors which alternate in typerx ridge and remain constant in typey ridge On the lower pair small circles mark 1211 T01 island sites cf 0 located symmetrically about the central axis of the typex ridge ne line other Systems Chambliss Wilson Chiang PRL 66 1721 1991 Co on Au 111 Fe amp Co on Cu 11 Co 011 N2 adsorbed Cu 100 amp Cu 110 FeAg on M0 110 Lithography 50 Liu UCD Phy250 2 2009 NanoFab SelfAssembly Nucleation2 b 1MLAu111 236A 1ML moon20 co 6 2 FIG 1 Reconstructed Aulll surface 730x730 132 with 1 FIG 4 m 3ML Co coverage on Aullll 1600x300 All rotational domains along the 112 direction forming an or I Al his coverage ihe cu law is already cunligunus b 7ML dered zigzag pattern 2 Co coverage SZOOX I600 Aquot showing 394 persisting regular ar ray of Co islands related lo Ihc initial nucleation paucrn 0 l I l Vo1gt1ander Meyer Amer o 200 A00 DISi nCE A PRB 44 10354 1991 FIG 2 a 03ML Co coverage on Auil l 1 1600gtlt 1600 A2 2MLhigh polygonal Co islands nucleate at the kinks of the Aulll zigzag reconstruction 13 Height variation along the line indicated in a Lithography 51 Liu UCD Phy2502 2009 NanoFab SelfAssembly Nucleation3 C0 pillars 0n Au 111 etc a lnAs2 GaAs Bi Iayer 4 BiIayer 3 BiIayer 2 BiIayer 1 Au substrate FIG 1 Principle of multilayered systems of selforganized clots a Strain energy minimization induces vertical sclflt alignment of dots from successive layers 4 b Present process dots come in vertical vicinity or even direct contact if the interlayerspacer thickness is suf ciently reduced Fruchart Klaua Barthel Kirschner PRL 83 2769 1999 Lithography FIG 2 The pillargrowth process illustrated by STM views of the top surface For steps a c a crosssection View of real data is provided along with a schematic view a A er deposition of a nominal thickness of 02 AL of Co on Au111 at 300 K The main STM image is 300 X 300 nm ross section reveals that the dots are 2 AL high b Alter deposition of Au up to the completion of the fourth atomic layer step 2 in the text The STM image is 60 X 35 nm The hollows are about 006 nm deep which is consistent with twice the height difference between a bulk hcp Co0001 AL 0205 nm and an fcc Au111 AL 0235 nm e A er deposition of the second layer of Co dots step 3 in the text The STM image is 65 X 25 nm The hollows are about 012 nm deep ie 4 times the height difference between a C0 and a Au atomic layer suggesting that the dots are now 4 AL high d A er 2 AL of Co have been stacked 300 X 300 nm STM image A selforganized array of pillars of nearly pure Co has been h h formed with pillars 3 nm in diameter and 55 nm 1g Liu UCD Phy2502 2009 NanoFab
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