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A Nanowire FET Switch Integrated Microelectrode for High-Resolution Retinal Prosthetic System
고해상도 망막 보철 시스템을 위한 나노와이어 FET 스위치를 내장한 미세 전극

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dc.contributor.advisor조동일-
dc.contributor.author이상민-
dc.date.accessioned2017-07-13T06:56:50Z-
dc.date.available2017-07-13T06:56:50Z-
dc.date.issued2013-02-
dc.identifier.other000000009157-
dc.identifier.urihttp://hdl.handle.net/10371/118891-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2013. 2. 조동일.-
dc.description.abstractRetinal degenerative diseases result in a progressive degeneration of photoreceptors in the retina and eventually lead to complete blindness. While, pharmaceutical treatments and gene therapy may help maintain vision in the early stages of degeneration, survival of the inner nuclear and retinal ganglion layers support the approach to partially restore vision by electrical stimulation of surviving neurons using neural prostheses devices. However, tasks that require a fine resolution of visual information such as facial recognition and reading cannot be achieved, due to the limited number of microelectrode array caused by the wiring complexity. In this dissertation, novel silicon nanowires FET switch on a flexible substrate to implement a high-resolution microelectrode array for retinal prosthesis is presented. The silicon nanowire FET switch allows choosing active microelectrode for electrical stimulation of retina by selecting a specific row and column. The proposed microelectrode array has 32 × 32 pixels with unit pixel size of 100 μm × 100 μm. Each unit pixel consists of a stimulation electrode, a ground electrode, a nanowire FET switch, a data line, and a scan line. The data line and scan line, which is connected with outer pad, chooses a specific nanowire FET switch to activate microelectrode for electrical stimulation. The electrical characteristics of silicon nanowire FET switch are measured to evaluate the device performance. After fabrication the silicon nanowire FET switch integrated microelectrode array, experiment under phosphate buffered saline (PBS) solution is performed to evaluate the device characteristics. The threshold voltage, current on/off ratio, and on-resistance of the fabricated silicon nanowire FET switch is measured to be - 0.4 V, 1 × 10^7, and 43 kΩ at gate voltage of - 5V, respectively. The maximum allowable current injection limit of the fabricated silicon nanowire FET switch integrated microelectrode is measured as 48 μA at pulse duration of 1 ms. The presented performance evaluation results show that the proposed nanowire FET based microelectrode can be used for the implementation of high-resolution retinal prosthetic system.-
dc.description.tableofcontentsAbstract i
Contents iii
List of Figures vi
List of Tables ix
Chapter 1 1
1.1 Background 2
1.1.1 Visual Perception 2
1.1.2 Retinal Degeneration and Treatments 4
1.2 Artificial Vision 7
1.2.1 Electrical Stimulation Method 7
1.2.2 Electrical Retinal Stimulation 12
1.2.3 Requirement for Microelectrode Array 17
1.3 High-Resolution Microelectrode Array 19
1.3.1 Issues due to High-Density 19
1.3.2 Previous Results for High-Resolution MEA 24
1.4 Contribution and Overview 28
Chapter 2 31
2.1 System Configuration 31
2.1.1 Motivation 31
2.1.2 Nanowire-Based Retinal Prosthetic System 34
2.2 Interface Impedance 47
2.3 Design of High-Resolution MEA 51
2.3.1 Design of Nanowire FET Switch 51
2.3.2 Mask Layout 57
2.3.3 Design Verification 60
Chapter 3 66
3.1 Fabrication Process 66
3.1.1 Fabrication of Silicon Nanowire Array 66
3.1.2 Fabrication of Nanowire Integrated MEA 76
3.2 Fabrication Result 86
3.2.1 Fabrication Result of Silicon Nanowire Array 86
3.2.2 Fabrication Result of Nanowire Integrated MEA 93
3.2.3 Fabrication of MEA for Stimulation Efficiency Evaluation 102
Chapter 4 105
4.1 Nanowire FET Switch 105
4.1.1 Experimental Set-Up 105
4.1.2 Electrical Characteristics 109
4.2 Current Stimulation Property 115
4.2.1 Interface Impedance 115
4.2.2 Maximum Allowable Current Injection Limit 123
4.3 Nanowire FET Switch Integrated MEA 129
4.3.1 Experimental Set-Up 129
4.3.2 Performance Characteristics 130
Chapter 5 136
5.1 Conclusions 136
5.2 Future Works 138
Appendix A: Code for SENTAURUS simulation 141
Appendix B: Current stimulator 145
Bibliography 146
Abstract in Korean 159
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dc.formatapplication/pdf-
dc.format.extent42506610 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectRetinal prosthesis-
dc.subjectMicroelectrode array-
dc.subjectNanowire FET switch-
dc.subjectHigh resolution-
dc.subjectFlexible substrate-
dc.subject.ddc621-
dc.titleA Nanowire FET Switch Integrated Microelectrode for High-Resolution Retinal Prosthetic System-
dc.title.alternative고해상도 망막 보철 시스템을 위한 나노와이어 FET 스위치를 내장한 미세 전극-
dc.typeThesis-
dc.contributor.AlternativeAuthorSangmin Lee-
dc.description.degreeDoctor-
dc.citation.pagesix, 160-
dc.contributor.affiliation공과대학 전기·컴퓨터공학부-
dc.date.awarded2013-02-
Appears in Collections:
College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Electrical and Computer Engineering (전기·정보공학부)Theses (Ph.D. / Sc.D._전기·정보공학부)
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