PTC Proposal

Seongjin JangSeptember 09, 2013

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.

Fabrication Process FlowStep 1: 4’’ Silicon wafer with 200nm SiO2, 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, 90C)•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:

1. 4’ wafer with 200 nm SiO2

3.Thermal physical deposition of Au/Ti

5. ICP/RIE etch SiO2

6. XeF2 etch of 5 micron Si substrate

Fabrication process

2. Photolithography

4. Lift-off

Example 1 (cont’d):

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:

Process

Silicon Oxide Wafer

Au/Cr Pad

Graphene

Nanomanipulator ProbeOr Probe Station probe

Example 2 (cont’d):