ESW 05/18/2017. Optimized by Sarah Muschinske Fall 2016 - Spring 2017. This is the optimized version.

Required Materials

• As-grown Bi or BiSb on Si(111). 2 cm x 1 cm piece optimal for ease of transfer + efficient use of Bi / Si(111) wafer.

• Nitto Denko single sided thermal release tape - 3.7 N/20mm tape used here (nominally releases at 90 C)

• Transfer substrate (so far have used Si(111), SiO2/Si(100) with and without alignment markers, YIG, and glass slides).

Procedure

Setup

• Turn on hot plate to 210 C

  • To standardize process, used aluminum foil-coated hot plate in bat cave fume hood

• Quick solvent rinse of transfer substrates and as-grown Bi

  • Setup solvent rinse

    • Solvent hood E5 in main clean room

    • Set cloth chem wipe on outside of fume hood

    • Keep sample containers outside of fume hood to avoid contamination

    • Get out waste beaker kept in fume hood

  • Hold samples with metal tweezers and rinse over waste beaker

    • 15 s acetone

    • 30 s IPA

    • dry with N2 blow gun over chem wipe

  • Clean up hood

    • Pour waste liquid into large waste bottle to the side of the fume hood

    • Never pour solvent waste down the drain

    • Chem wipe in solvent waste container

• Set up transfer area in bat cave

  • Transfer holder, scissors, tape, chem wipes

  • Do transfers in large sample holder to avoid tape sticking to wipes

  • Cut tape - about 1x width of sample, 1.5x length of sample

Bi delamination

• Press tape piece onto sample, so that tape overhangs one end of sample

• Smooth our any air bubbles gently with fingers

• Turn sample over, and wedge plastic tweezers between Bi and tape

• Firmly grip sample with tweezers, and pull tape quickly from overhanging end

• Bi should be removed with the tape

Transfer to new substrate

• Press Bi with tape onto second substrate (Bi-side down)

  • Pressing rather than rolling/smoothing motion avoids damaging Bi

• Trim tape edges - this step is very important, as it prevents tape from sticking to / pushing Bi away from the hot plate, which can cause uneven heating

• Put Tape/Bi/substrate stack onto pre-heated hot plate

• Tape changes color as it releases - should happen very quickly

• After release, remove Bi/substrate and tape from hot plate

Delamination Procedure Images