• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.4
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• pp.293-298
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• 2006

Thermopiezoelectric method, using poly silicon heater and a piezoelectric sensor, was proposed for writing and reading in a probe based data storage system. Resistively heated tip writes data bits while scanning over a polymer media and piezoelectric sensor reads data bits from the self-generated charges induced by the deflection of the cantilever. 34${\times}$34 array of thermopiezoelectric nitride cantilevers were fabricated by a single step wafer level transfer method. We analyzed the noise level of the charge amplifier and measured the noise signal. With the sensor and the charge amplifier 20mn of deflection could be detected at a frequency of 10KHz. Reading signal was obtained from the cantilever array and the sensitivity was calculated.

• Journal of Biomedical Engineering Research
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• v.22 no.2
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• pp.145-150
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• 2001

대뇌 피질에 삽입하여 깊이에 따라 신경 신호를 기록하기 위한 탐침형 반도체 미세전극 어레이(depth-type silicon microelectrode array, 일명 SNU probe)를 제작하였다. 붕소를 확산시켜 생성된 고농도 p-type doping된 p＋ 영역을 습식식각 정지점으로 사용하는 기존의 방법과 달리 실리콘 웨이퍼의 앞면을 건식식각하여 원하는 탐침 두께만큼의 깊이로 트렌치(trench)를 형성한 후 뒷면을 습식식각하는 방법으로 탐침 형태의 미세 구조를 만들었다. 제작된 반도체 미세전극 어레이의 탐침 두께는 30 $\mu\textrm{m}$이며 실리콘 건식식각을 위한 마스크로 6 $\mu\textrm{m}$ 두께의 LTO(low temperature oxide)를 사용하였다. 탐침의 두께는 개발된 본 공정을 이용해서 5~90 $\mu\textrm{m}$ 범위까지 쉽게 조절할 수 있었다. 탐침의 두께를 보다 쉽게 조절할 수 있게 됨에 따라 여러 신경조직에 필요한 다양한 구조의 반도체 미세전극 어레이를 개발할 수 있게 되었다. 본 공정을 이용해서 개발된 4채널 SUN probe를 사용하여 흰쥐의 제1차 체감각 피질에서 4채널 신경 신호를 동시에 기록하였으며, 전기적 특성검사에서 기존의 탐침형 반도체 미세전극, 텅스텐 전극과 대등하거나 우수한 신호대 잡음비(signal to noise ratio, SNR)특성을 가짐을 확인하였다.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.22-25
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• 2005

In this research, a wafar-level transfer method of cantilever array on a conventional CMOS circuit has been developed for high density probe-based data storage. The transferred cantilevers were silicon nitride ($Si_3N_4$) cantilevers integrated with poly silicon heaters and piezoelectric sensors, called thermo-piezoelectric $Si_3N_4$ cantilevers. In this process, we did not use a SOI wafer but a conventional p-type wafer for the fabrication of the thermo-piezoelectric $Si_3N_4$ cantilever arrays. Furthermore, we have developed a very simple transfer process, requiring only one step of cantilever transfer process for the integration of the CMOS wafer and cantilevers. Using this process, we have fabricated a single thermo-piezoelectric $Si_3N_4$ cantilever, and recorded 65nm data bits on a PMMA film and confirmed a charge signal at 5nm of cantilever deflection. And we have successfully applied this method to transfer 34 by 34 thermo-piezoelectric $Si_3N_4$ cantilever arrays on a CMOS wafer. We obtained reading signals from one of the cantilevers.

• The Journal of the Acoustical Society of Korea
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• v.29 no.3
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• pp.165-172
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• 2010

It is important to determine the communicational method that knows the characteristic of phase variation along transducers formed array within the water column in actual underwater environment and the correlation between transducers. This paper analyzes the characteristic of phase variation that vary on different locations by probe signals that transmitted from a probe source and received along transducers. This paper calculated the theoretical transmission capacities by the analyzation of the correlation between transducers through changing the distance between transducers and the distance between a probe source and transducers.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2128-2130
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• 2004

High throughput analysis using a DNA chip microarray is powerful tool in the post genome era. Less labor-intensive and lower cost-performance is required. Thus, this paper aims to develop the multi-channel type label-free DNA chip and detect SNP (Single nucleotide polymorphisms). At first, we fabricated a high integrated type DNA chip array by lithography technology. Various probe DNAs were immobilized on the microelectrode array. We succeeded to discriminate of DNA hybridization between target DNA and mismatched DNA on microarray after immobilization of a various probe DNA and hybridization of label-free target DNA on the electrodes simultaneously. This method is based on redox of an electrochemical ligand.

• Journal of Biomedical Engineering Research
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• v.26 no.4
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• pp.207-214
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• 2005

Breast cancer detection using electrical impedance techniques is based on numerous experimental findings that cancerous tissues have higher electrical conductivity values than normal tissues. Lately, by taking advantage of the structure of current flows underneath a planar probe of array electrodes, a mathematical formula to find lesions from a measured trans­admittance map has been derived. In order to experimentally validate its mathematical analysis and the suggested lesion estimation algorithm, we developed a 256-channel trans-admittance scanner (TAS) for probing anomalies underneath a planar array of electrodes. In this paper, we describe the design and implementation of the TAS. Its performance together with the lesion estimation algorithm was evaluated using saline phantoms. Further studies are proposed to validate the system on human subjects.

• Journal of the Optical Society of Korea
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• v.18 no.2
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• pp.151-155
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• 2014

Although various ophthalmic imaging methods, including fundus photography and optical coherence tomography, have been applied for effective diagnosis of ocular diseases with high spatial resolution, most of them are limited by shallow imaging penetration depth and a narrow field of view. Also, many of those imaging modalities are optimized to provide microscopic anatomical information, while functional or cellular information is lacking. Compared to other ocular imaging modalities, photoacoustic imaging can achieve relatively deep penetration depth and provide more detailed functional and cellular data based on photoacoustic signal generation from endogenous contrast agents such as hemoglobin and melanin. In this paper, array-based ultrasound and photoacoustic imaging was demonstrated to visualize pigmentation in the eye as well as overall ocular structure. Fresh porcine eyes were visualized using a real-time ultrasound micro-imaging system and an imaging probe supporting laser pulse delivery. In addition, limited photoacoustic imaging field of view was improved by an imaging probe tilting method, enabling visualization of most regions of the retina covered in the ultrasound imaging.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.4
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• pp.410-414
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• 2004

High throughput analysis using a DNA chip microarray is powerful tool in the post genome era. Less labor-intensive and lower cost-performance is required. Thus, this paper aims to develop the multi-channel type label-free DNA chip and detect SNP (Single nucleotide polymorphisms). At first, we fabricated a high integrated type DNA chip array by lithography technology. Various probe DNAs were immobilized on the microelectrode array. We succeeded to discriminate of DNA hybridization between target DNA and mismatched DNA on microarray after immobilization of a various probe DNA and hybridization of label-free target DNA on the electrodes simultaneously. This method is based on redox of an electrochemical ligand.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.5
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• pp.286-292
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• 2004

In this study, an integrated microelectrode array was fabricated on glass slide using microfabrication technology. Probe DNAs consisting of mercaptohexyl moiety at their 5-end were spotted on the gold electrode using micropipette or DNA arrayer utilizing the affinity between gold and sulfur. Cyclic voltammetry in 5mM ferricyanide/ferrocyanide solution at 100 ㎷/s confirmed the immobilization of probe DNA on the gold electrodes. When several DNAs were detected electrochemically, there was a difference between target DNA and control DNA in the anodic peak current values. It was derived from specific binding of Hoechst 33258 to the double stranded DNA due to hybridization of target DNA. It suggested that this DNA chip could recognize the sequence specific genes. It suggested that multichannel electrochemical DNA microarray is useful to develop a portable device for clinical gene diagnostic System.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.402-403
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• 2006

This research aims to develop the multiple channel electrochemical DNA chip using microfabrication technology. At first, we fabricated a high integration type DNA chip array by lithography technology. Several probe DNAs consisting of thiol group at their 5-end were immobilized on the gold electrodes. Then target DNAs were hybridized and reacted. Cyclic voltammetry showed a difference between target DNA and control DNA in the anodic peak current values. Therefore, it is able to detect a plural genes electrochemically after immobilization of a plural probe DNA and hybridization of non-labeling target DNA on the electrodes simultaneously. It suggested that this DNA chip could recognize the sequence specific genes.