Title Page
Abstract
Contents
1. Introduction 10
1.1. Research of graphene neural electrodes 10
1.2. Materials and equipments 12
1.2.1. Materials 12
1.2.2. Fabrication and measurement equipments 16
1.3. Structure of electrode 19
2. Fabrication process 21
2.1. Recipe 21
2.2. Key process 23
2.2.1. Photoresist image reversal and lift-off 23
2.2.2. Graphene wet transfer and etching 26
2.3. Fabricated electrode 28
3. Measurement and analysis 31
3.1. Measurement methods and conditions 31
3.2. Raman spectroscopy 35
3.3. Cyclic Voltammetry 37
3.4. Electrochemical impedance spectroscopy 40
3.5. Electromyography 48
4. Design simulation 52
5. Conclusion and discussion 55
References 57
Abstract (Korean) 61
[Table 1] Equivalent circuit components value 47
[Figure 1] (a) Parylene-C dimer powder, (b) Parylene-C molecular structure 13
[Figure 2] Graphene honeycomb structure 14
[Figure 3] COP molecular structure 15
[Figure 4] Fabrication equipments (a) parylene coater, (b) spin coater, (c) aligner, (d) e-beam evaporator, (e) reactive ion... 17
[Figure 5] Measurement equipments (a) Potentiostat, (b) bioAmp processor 18
[Figure 6] Metal-only (left), graphene channel (center), graphene/metal hybrid (right) design 20
[Figure 7] Fabrication process flow 22
[Figure 8] Image reversal process 24
[Figure 9] Schematic of metal deposition based on the type of PR pattern. 25
[Figure 10] Graphene wet transfer 26
[Figure 11] (a) Fabrication regions for each electrode type on the wafer, (b) fabricated electrodes 30
[Figure 12] three electrode measurement system 32
[Figure 13] EMG measurement 34
[Figure 14] Raman spectroscopy of graphene, parylene-C 36
[Figure 15] (a) CV graph, (b) cathodic CSC standard deviation 39
[Figure 16] Impedance plot of (a) metal-only, (b) graphene channel, and (c) graphene/metal hybrid 41
[Figure 17] The average impedance plots for the three types of electrodes 42
[Figure 18] Nyquist plot of (a) three types of electrode, (b) metal-only, (c) graphene channel, (d) graphene/metal hybrid... 45
[Figure 19] EMG measurement data of (a) graphene channel electrode, (b) graphene/metal hybrid electrode, (c) signal... 51
[Figure 20] (a) 256 channel electrode design (left hybrid electrode, right metal-only electrode), (b) comparison of... 54