1. PTC Proposal Seongjin Jang September 09, 2013

2. Submit Application To PTC All the users should submit their process-related information to Process Technology Committee (PTC) for approval. The purpose of this practice is for the PTC to understand exactly what the users are trying to do and to examine the users’ ability to safely perform their tasks. Once the PTC approves the process, the users will be notified. The users can use the equipment if they have completed the safety test and equipment training. Violation of the rules will result in being disqualified.

3. Fabrication Process Flow Step 1: 4 ’’ Silicon wafer with 200nm SiO 2, single side polished Step 2: Photolithography Image Reversal photo and develop HMDS, spin coat (coat recipe: 6sec@0.5krpm, 6sec@0.75krpm, 30sec@5krpm to get ~1.8um photoresist) Prebake (30min, 90  C) Expose (MA6 with mask, 1.0-1.4 sec ) Post-bake ( 100° C, 25 min or 65 sec 120 °C hotplate) Flood exposure without mask: (60sec on MA6) Develop (MIF 422) Step 3: Ti/Au Electrode Deposition Standard thermal deposition Target deposition: 70A Ti Target deposition: 2000A Au Step 4: Ti/Lift-off Acetone lift-off on electrode; followed by methanol and 2-propanol for cleaning. Ultrasonic ~2-3mins for quicker lift-off and clearing lift-off residues. Cleaning of solvents and contaminants with: acetone / methanol / 2-propanol and multiple rinse dumps. Step 5: Silicon oxide etch ICP/RIE etch of silicon oxide Step 6: Silicon etch Dry etch of 5 micron Si Substrate using XeF2 Example 1:

4. 1. 4’ wafer with 200 nm SiO 2 3.Thermal physical deposition of Au/Ti 5. ICP/RIE etch SiO 2 6. XeF2 etch of 5 micron Si substrate Fabrication process 2. Photolithography 4. Lift-off Example 1 (cont’d):

5. Electrical Characterization of Graphene using Nanomanipulator Purpose: voltage-current measurements of graphene flakes with electrical contacts Equipments required: SEM with nanomanipulator or Probe Station Parameters: Applied voltage (typically less than 10 V) and currents (less than 1 mA) Note : – The electrical contacts on the graphene will be fabricated outside of the MDL. – Only characterization will be done using the requested equipments. Example 2:

6. Process Silicon Oxide Wafer Au/Cr Pad Graphene Nanomanipulator Probe Or Probe Station probe Example 2 (cont’d):