진동 센서용 압전 박막의 제조 및 그 특성 분석

윤화중,서일환,구경환,임무열,이진호 경북대학교 센서기술연구소 1993 연차보고서 Vol.1993 No.-

졸-겔 spin-coating법을 이용하여 PZT 압전 박막을 제작하고 그 물리적 및 전기적 성질을 평가하여 진동 측정용 센서로서의 적용 가능성을 검토하였다. PZT의 원료로는 Pb-acetate, Zr-propoxide 그리고 Ti-propoxide를 사용하였다 SEM 단면사진의 결과 하부전극 금속이 silicate화 하였고, SIMS 분석결과 Si와 하부전극의 금속이 PZT 박막의 상층부까지 확산된 것을 알 수 있었다. X-RD로 박막의 결정성을 조사한 결과 하부전극을 Pt로 한 박막과 buffer 층으로 Ti를 증착한 박막에서 강한 perovskite 상이 나타났다. D-E Hysterisis 곡선을 관찰한 결과 강유전성을 나타내며, 항전계는 33.3 ㎸/㎝, 잔유분극은 1.92 C/℃ 이었다. 박막의 비유전율은 57이었다. 박막의 resistance와 impedance의 반공진 주파수는 612 ㎒이고, 이때의 resistance 값은 14 ㏀이었다. 박막의 진동에 대한 주파수 응답 곡선을 측정 결과 12000 ㎐ 이하 저주파 영역에서는 응답 특성이 떨어지고 12000 ㎐ 이상의 어느 정도 높은 주파수 영역에서 응답 특성이 양호하다는 것을 알 수 있었고, 20000 ㎐ 100 ㏈(V)의 진동에 대해 151.4 ㎶의 응답을 나타내었다. PZT thin film was prepared by Sol-Gel spin-coating method and it's physical and electrical caracteristics were appreciated. Pb acetate, Zr propoxide and Ti propoxide used for the starting material to fabricate PZT coating solution. The cross-sectional SEM micrograph showed that the metals of lower electrode was silicated. The SIMS depth profile indicated that the metal of lower electrode and silicon diffused up to the upper part of PZT thin film. For the X-RD data of PZT thin film, the thin film on Pt substrate and with Ti buffer layer had strong perovskite phase. The PZT thin films measured by Sawyer-Tower circuit showed feroelectric characteristic representating D-E hysterisis curve. The remanent polarization and coercive field of the film was 1.92 C/㎠ and 33.3kV/㎝. Dielectric constant of Film is 57. The resistance and impedance antiresonance frequency was 612 ㎒, and the resistance was 14 ㏀ at that frequency. The frequency response curve of PZT film showed that the PZT film responded sensitively at the high frequency, and response voltage of PZT film was 151.4 ㎶ at 20,000 ㎐ 100 ㏈(V) frequency.

3成分界 壓電薄膜을 이용한 超高主波用 素子의 開發 및 그 特性 分析

尹和重,徐日煥,丘庚完,林武悅,李珍昊 경북대학교 센서기술연구소 1995 연차보고서 Vol.1995 No.-

유기금속을 사용한 졸-겔 스핀 코팅법으로 PZT-PNN 박막을 제조하였으며, diethanolamine을 안정화물질로 사용하였다. PT:PZ:PNN의 코팅 용액의 mol%는 각각 #1 (50:40:10), #2(50:30:20), #3(45:35:20), #4(40:40:20), #5(40:50:10), #6(35:45:20) 그리고 #7(30:50:20)으로 제조하였다 스핀 코팅된 박막의 잔류 유기물을 제거하기 위해 350℃에서 예비소결을 하였고, 박막의 결정화를 위해 450℃ ∼ 700℃에서 소결하였다. 백금 기판과 Pt/TiN/Ti/TiN/Si 기판 위에 박막을 성장하였으며, 500℃의 소결에서도 perovskite 상이 출현하였다. 결정성이 가장 양호한 소결온도는 700℃이었다. Sawyer-Tawer 회로를 이용하여 박막의 P-E 이력곡선을 관찰하였다. 박막의 항전계와 잔류분극은 각각 28.8 ㎸/㎝과 18.3 μC/㎠이었다. 유전상수 K는 128 ∼ 1120의 값을 나타내었고, 상경계(40:40:20 mol%)에서 최대값을 보여주었다. 박막의 진성파괴전압은 27.0 ∼ 60.0 MV/m이었으며, 소결온도가 올라갈수록 파괴전압은 낮아지는 경향을 나타내었다. 결정성과 전기적 특성을 고려하면 550℃의 소결온도에서 박막의 특성이 가장 양호하다고 생각된다. #4 40:40:20 mol%의 박막을 이용하여 초고주파 필터를 제작하였다. ring-dot 분할전극형 필터의 경우 공진주파수는 435.26 ㎒이고 투과손실은 -0.20 ㏈이며, 반공진주파수는 1905.11 ㎒ 투과손실은 -34.30 ㏈이었다. 두께진동을 이용한 필터의 경우 공진주파수는 1035.17 ㎒ 투과손실은 -0.86 ㏈, 반공진주파수는 2310.07 ㎒ 투과손실은 -29.11 ㏈이며, 탄성표면파 필터의 경우 공진주파수는 228.28 ㎒ 투과손실은 -0.62 ㏈, 반공진주파수는 1352.86 ㎒ 투과손실은 -35.68 ㏈이었다. PbTiO_3-PbZrO_3-Pb(Ni_(1/3)Nb_(2/3)O_3)(PZT-PNN) thin films were been prepared from corresponding metal organics partially stabilized with diethanolamine by the sol-gel spin coating method. The each mol rates of PT:PZ:PNN solutions were #1(50:40:10), #2(50:30:20), #3(45:35:20), #4(40:40:20), #5(40:50:10), #6(35:45:20) and #7(30:50:20) respectively. The spin-coated PZT-PNN films were heat-treated at 350℃ for decomposition of residual organics, and were heat-treated at temperature between 450 ℃ and 750 ℃ for crystallization. The substrates, such as Pt and Pt/TiN/Ti/TiN/Si were used for the spin coating of PZT-PNN films. The perovskite phase was observed in the PZT-PNN films which were heat-treated at 500 ℃. The crystallization of the PZT-PNN films was optimized at 700 ℃ of sintering temperature. The P-E hysteresis curve was drawn by Sawyer- Tower circuit with PZT-PNN film. The coercive field and the remanent polarization of PZT-PNN film was 28.8 ㎸/㎝ and 18.3 μC/cm2 respectively. Its dielectric constants were shown between 128 and 1120, and become maximum value in MPB. The break down voltages of PZT-PNN films were shown between 27.0 and 60.0 MV/m. Crystalline and electrical characteristics of thin film indicate that characteristics of film is optimised at 550 ℃ sintering temperature. S.H.F. filter was made of #4 40:40:20 mol% thin film. For the case of ring-dot electrode type filter, resonance frequency and transmission loss were 435.26 ㎒ and -0.20 ㏈, and antiresonance frequency and transmission loss were 1905.11 ㎒ and -34.30 ㏈. For the case of thickness vibration filter, resonance frequency and transmission loss were 1035.17 ㎒ and -0.86 ㏈, and antiresonance frequency and transmission loss were 2310.07 ㎒ and -29.11 ㏈. For the case of SAW filter, resonance frequency and transmission loss were 228.28 ㎒ and -0.62 ㏈, and antiresonance frequency and transmission loss were 1352.86 ㎒ and -35.68 ㏈.

진동 센서용 3성분계 압전 박막의 제조 및 그 특성 분석(Ⅱ)

윤화중,서일환,구경완,임무열,이진호 경북대학교 센서기술연구소 1994 연차보고서 Vol.1994 No.-

3성분계 PZT 압전박막의 출발물질로는 Pb acetate, Zr propoxide, Ti propoxide, Ni acetate, Nb ethoxide를 사용하였고, 용매로는 iso metoxy ethanol을 사용하였다. 가수분해를 방지하기 위해 coating 용액에 diethanolamine을 첨가하여 chelate화합물을 형성하였고, coating 전에 H_2O를 첨가하여 M-O-M 구조의 polymer gel이 형성되도록 하여 내구성이 강한 박막을 제작하였다. Coating 용액의 열중량 분석 결과, 건조 온도는 90℃∼120℃, 예비소결 온도는 300℃∼400℃가 적합한 것으로 판단되었다. 박막의 SEM 단면 촬영 결과, 하부기판과 하부전극 사이의 TiN-Ti-TiN buffer층이 박막과 하부 기판과의 반응을 막아주어 막이 잘 형성되었으며, 각 계면에서도 별다른 이상이 발견되지 않았다. X-RD로 박막의 결정성을 조사한 결과 Pt 기판과 Pt/TiN-Ti-TiN/Si 기판 공히 550℃의 소결에서 결정성이 가장 양호하며 600℃ 이상에서는 과소결 되는 것으로 판단된다. D-E Hysterisis 곡선을 관찰한 결과 이 박막은 강유전체임을 확인했으며, 항전계는 28.8 ㎸/㎝, 잔유분극은 18.3 μC/㎠ 이었다. 박막의 I-V 특성 결과는 다음과 같다. ◁표 삽입▷(원본을 참조하세요) 3성분계 PZT 박막의 C-V 특성곡선을 측정한 결과 각 조성비에 대한 비유전율은①(50:40:10)은 406, ②(50:30:20)은 1084, ③(45:35:20)은 723, ④(40:40:20)은 316이었다. In order to make the three compound piezoelectric thin film, the Pb acetate, Zr propoxide, Ti propoxide, Ni acetate, Nb ethoxide are used as starting materials, and iso metoxyethanol was used as a solvent. After DEA (diethanolamine) is added in to the solution, the coating solution and chelate compound are made in order to the phenomenon of hydrosys was prevented. Before coating, H2O was added in to the solution, the polymer gel which is M-O-M structure was formed, and then the strong durable film was made. As a result of the analysis by TGA, dry temperature was between 90℃ and 120℃, presintering temperature was indicated between 300℃ and 400℃. As a result of observing the SEM cross section of the film in the pictures were taken, the reaction of membrane and substrate caused by TiN-Ti-TiN buffer layers, and the abnormality was not detected in the boundary surfaces. As a result of checking of the X-RD film crystallization, the crystallization is best at 550℃ sintering and at 600℃ upper the over sintering is made on the both of Pt substrate and Pt/TiN-Ti-TiN/Si substrate. As a result of observing the D-E hysterisis curve, in the thin film the strong dielectricity was found and coercive field was 28.8 ㎸/㎝, the remanent polariztion was 18.3 μC/㎠. Ⅰ-Ⅴ characteristic chart is as following ◁표 삽입▷(원본을 참조하세요) As a result of measuring the C-V characteristic curve of the three compound piezoelectric thin film, the relative dielectric constant was ①(50:40:10)→406, ②(50:30:20)→1084, ③(45:35:20)→723, ④(40:40:20)→316.

졸겔법으로 제작한 PZT-PNN 박막의 전기적 특성

윤화중,임무열,구경완 충남대학교 기초과학연구소 1995 忠南科學硏究誌 Vol.22 No.2

PbTiO_3-PbZrO_3-PbNi_1/3Nb_2/3O_3(PZT-PNN) thin films have been prepared from corresponding metal organics partially stabilized with diethanolamine through the sol-gel spin coating process. The each mol rates of PT:PZ:PNN sol solutions were #1(50:40:10), #2(50:30:20), #3(45:35:20) and #4(40:40:20). The spin-coated PZT-PNN films were heat-treated at 350℃ for decomposition of residual organics, and were heat-treated at temperature between 450℃ and 750℃ for crystallization. The substrates, such as Pt and Pt/TiN/Ti/TiN/Si were used for the spin coating of PZT-PNN films. The perovskite phase was observed in the PZT-PNN films which were heat-treated at 500℃. The crystallization of the PZT-PNN films was optimized at 700℃ of sintering temperature. The P-E hysteresis curve was drawn by Sawyer-Tower circuit with PZT-PNN film. The coercive field and the remanent polarization of PZT-PNN film was 28.8 kV/㎝ and 18.3 μC/㎠ respectively. Its dielectric constants K were shown between 128 and 1120, and become maximum value in MBP. The Curie pont of PZT-PNN film indicated 330℃ according to the measurement of dielectric constant. The break down voltages of PZT-PNN films were shown between 27.0 and 60.0 MV/m.

압전소자를 이용한 광음향 스펙트럼에 관한 연구

윤화중,금채,허복회,김유배 충남대학교 자연과학연구소 1988 忠南科學硏究誌 Vol.15 No.1

The development of photoacoustic spectroscopy(PAS) was carried out for liquid sample by using piezoelectric transducer(PZT). In order to carry out the work the cell was designed and made, and its characteristics of frequency responses were investigated. The PAS of distilled water was obtained by using the cell and detected by PZT in visible lights wavelength range of 400∼500nm from Halogen lamp light source. According to this study, it shows that the development of PAS for liquid sample by using PZT is more easier and simpler than by using microphone detector.

消音器의 音響減衰에 關한 硏究

윤화중,홍은숙,전관수 충남대학교 자연과학연구소 1989 忠南科學硏究誌 Vol.16 No.2

In order to investigate the acoustical attenuation effects from simple expansion chamber type muffler the following experiments were carried out ; the spectrum analyzer which has 25Hz analyzing frequency intervals was devised. The changing of acoustical attenuation frequency intervals was devised. The changing of acoustical attenuation effects were observed by varying the diameter and the length of the muffler. The diffuser was attached to the muffler in order to decrease the sound pressure levels more and then the acoustical attenuation effects were investigated. The phenomena on the sound wave surface was curvatured and visualized by the diffuser was confirmed in photographic developing of the attenuation wave.

Photoacoustic Spectroscopy에 의한 화합물 반도체의 물성연구

윤화중,금채,양준묵 충남대학교 기초과학연구소 1984 연구논문집 Vol.5 No.-

When chopped light inpinges on some condenced matters such as HgS, HgI_2 and GaSe semiconductors, in an enclosed cell, the acoustic signals are produced within the cell. These acoustic signals were detected by using a gas-phase microphone in order to investigate the physical propesties of the samples. In order to carry out investigation, PA-cell was first disigned and made so as to produce higher sensitivity to acoustic signals. Second, an analysis of the photoacoustic spectrum of the various compounds was carried out to obtain the intensity of the PA-signal in terms of light wave-length and to calculate the energy band gaps occurring according to energy transition. The agreement between the results obtained by this conventional PAS technique and the results obtained by the optical spectrum method was good. In additional analysis conducted on the basis of the R-G theory and the Sze theory are capable of determining the characteristics of energy transition of semiconductors.

갑상선 전절제술 및 중심 경부 림프절 절제술에 따른 혈중칼슘치 저하에 대한 연구

고중화,안성윤,김휘준,신지철 대한이비인후과학회 1999 대한이비인후과학회지 두경부외과학 Vol.42 No.12

충남대학교 기초과학분야의 효율적 육성에 관한 연구

윤화중,진성일,윤민중,윤혜수,이영하,최철규,이천배,신대현 충남대학교 자연과학연구소 1986 忠南科學硏究誌 Vol.13 No.2

Chungnam National University (CNU) is located in Daeduk Science Town, a center of science and technology in Korea, and it is expected to play an important role in the development of science in Korea. With this in mind, the basic natural sciences at CNU should be more actively supported in both education and research. Accordingly analysis and comparison of the basic science program at major college in Korea as well as those in the USA and Europe has been performed. The current cooperative relationship between CNU and research institutes in the science town has also been analyzed. This study has resulted in propositions to make more efficient the upbringing of the basic sciences at CNU, by focusing on the following points ; a) to improve academic affairs, b) to make graduate studies substantial, c) to secure highly qualified faculty members, d) to increase cooperation in research between CNU and reserch institutes, e) to enlarge research laboratories and acquire more equipment and facilities.

DEA 첨가 금속 Alkoxide를 사용한 PZT 박막의 제조 및 특성 평가

윤화중,임무열,구경완,최명진 충남대학교 기초과학연구소 1994 忠南科學硏究誌 Vol.21 No.1

Lead acetate trihydrate, zirconium iso-propoxide and titanium iso-propoxide used for the starting material to fabricate PZT coating solution. Iso-metoxy-ethanol used for the solvent of the starting material. Adding diethanolamine formed the chelate compound and prevented the hydrosis of coating solution. The coating sol solution is changed to M-O-M structure polymer gel by adding H_2O, and the polymer gel has the more strong bonding force. The cross-sectional SEM micrograph of PZT thin film showed that the metal of lower electrode was silicated with SiO_2 of buffer layer. The SIMS depth profile for PZT thin film indicated that the metal of lower electrode and silicon was diffused up to the upper part of PZT thin film. For the X-RD data of PZT thin film, the thin film on Pt substrate and with Ti buffer layer had strong perovskite phase. The PZT thin films measured by Sawyer-Tower circuit showed feroelectric characteristic representating D-E hysterisis curve. The remanent polarization and coercive field of the film was 1.92 C/㎠ and 33.3kV/㎝. I-V characteristic curve showed that the leakage currents and break down voltages of PZT thin films on Ni/SiO_2/Si, Ti/SiO_2/Si, Pt/SiO_2/Si substrate was 1.43 × 10 exp (-10) A/㎠, 1.19×10 exp (-10) A/㎠, 2.28×10 exp (-10) A/㎠ and 0.334 MV/㎝, 0.33 MV/㎝, 0.11 MV/㎝ each. C-V curve indicated dielectric constant 57 The resistance antiresonance frequency of PZT film was 612 ㎒, and the resistance was 14 ㏀ at that frequency.