Fabricating an Electrically Actuated ValveSputter Deposition of PZT for use in microfluidic devicesMaterials: Bottom Wafer Fabrication Procedure(Note: Top Wafer Fabrication Steps same as Special K’s)Step 1: Start with Si SubstrateStep 2: Coat with SiNStep 3: Mask 1. Deposit Intermediate Oxide-Oxide-SiN-Titanium-Silicon-PDMS-PZT (Piezoelectric Lead Zirconate Titanate)-Platinum (Electrode)-Mask1-MaskStep 4: Mask 1. Deposit Titanium Mask 1 (Top View)Step 5: Mask 2. Deposit SiN Mask 2 (Top View) Step 6: Mask3. Deposit Platinum (Bottom Electrode)Anneal 500°C-700°CMask 3 (Top View)2Step 7: Mask 4. Deposit SiN Mask 4 (Top View)Step 8: Mask 5. Deposit PZT Mask 5 (Top View)Anneal 650°C-(30 sec.)Step 9: Mask 3. Deposit Platinum (Bottom Electrode)3Final Step 10: Deposit Thin Film PDMS (Flexible Layer)Design challenges, concerns, and comments- Dimensions are not specified- Not sure if some of the steps are even feasible (i.e. mask designs and deposition of materials used)- Insulation of thin PDMS layer from top Pt electrode- Ti diffuses along grain boundaries on the surface of Pt- First annealing step of Ti/Pt is a pre-annealing step necessary prior to annealing PZT. PZT layers may crack upon annealingConclusionElectrically actuated PZT materials have the potential to provide concise valve systems for microfluidic devices. However, this particular sample design may be difficult to manufacture due to limited resources, and time constraints.
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