• 대한전자공학회논문지SD
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• 제37권6호
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• pp.64-71
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• 2000

등간격, 동일 구조의 $Ti:LiNbO_3$ 세 도파로를 이용한 광스위치를 설계하고 제작하였다. 공도파로는 z-cut $LiNbO_3$ 기판상에 Ti를 내부 확산시켜 제작하였다. TM 모드 전파 손실을 줄이기 위하여 도파로 위에 $SiO_2$ 박막을 증착시킨 후, 광스위칭을 위하여 CPW(Coplanar Waveguide)구조 Al 전극을 형성시켰다. 가운데 도파로에 입사된 ${\lambda}=1.3{\mu}m$ 광에 대하여 세 도파로가 대칭적으로 detuning 되도록 전계 인가시 광 스위칭이 일어남을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.743-746
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• 2000

Metal-ferroelectric-insulator-semiconductor(MFIS) devices using Pt/$LiNbO_3$/Si structure were successfully fabricated. The dielectric constant of the AIN film calculated from the capacitance in the accumulation region in the capacitance-voltage(C-V) curve was about 8.2. The gate leakage current density of MIS devices using a aluminum electrode showed the least value of 1$\times$$1O^{-8}$A/$cm^2$ order at the electric field of 500kV/cm. The dielectric constant of $LiNbO_3$film on AIN/Si structure was about 23 derived from 1MHz capacitance-voltage (C-V) measurement and the resistivity of the film at the field of 500kV/cm was about 5.6$\times$ $1O^{13}$ $\Omega$.cm.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.397-398
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• 2005

Ferroelectric Lithium niobate ($LiNbO_3$) thin films are fabricated on $Al_2O_3$(0001) substrate using Pulsed Laser Deposition (PLD). The various deposition conditions such as substrate temperature, oxygen pressure, and post annealing condition are investigated to deposite c-axis oriented $LiNbO_3$ thin films. Highly c-axis oriented thin films are obtained under the conditions of working pressure of 100 mTorr, deposition for 10 min at $450^{\circ}C$, and in-situ annealing for 40 min. The $LiNbO_3$ thin films are chemically etched after electric poling and the etched configurations are studied by scanning electron microscope (SEM).

• 한국재료학회지
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• 제9권2호
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• pp.163-167
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• 1999

LiNbO$_3$films were prepared by an rf-magnetron sputtering technique using sintered target containing potassium. The potassium was included to help to fabricate stoichiometric LiNbO$_3$film. Structural and electrical properties of thin films was investigated as a function of deposition condition. Optimum sputtering conditions were rf power of 100W, working pressure of 1m Torr and substrate temperature of 58$0^{\circ}C$. The thin film was grown to (012) preferred orientation. The dielectric constant of the thin film LiNbo$_3$ fabricated under optimum condition was 55 at 1MHz. Average grain size is about 200$\AA$ and roughness of the film is small enough to apply to optic devices.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.235-238
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• 1998

Ferroelectric $LiNbO_3$ thin films were grown directly on Si(100) substrates by 13.55MHz RF magnetron sputtering system using a ceramic target ($Nb_2O_5/Li_2C0_3$ = 51.4/48.6). Because high temperature process have to avoided to prevent degradation of the interface (insulator/Si), $LiNbO_3$ thin films were deposited below $300^{\circ}C$. After as-deposited films were performed RTA treatments in an oxygen ambient at $600^{\circ}C$ for 60s, electrical measurements performed films before and after anneal treatment. In high field region, the leakage current density of the films after annealing was deceased about 4order and the resistivity of these was increased to about 5\times 10^{11} \Omega \cdot cm$ at 500kV/cm. In accumulation region of C-V curve, we calculated dielectric constant of thin film $LiNbO_3$ as 27.9 which is close to that of bulk value.

• 대한전자공학회논문지SD
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• 제37권11호
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• pp.50-58
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• 2000

Goodved $SiO_2$ 박막을 갖는 Mach-Zehnder(M-Z)형태의 $Ti:LiNbO_3$ 진행파 광변조기의 전극구조를 변화시켜가며 유한요소법에 의한 해석을 수행하였다. 최적의 설계치를 추출하였으며, 제작된 전극에 대하여 특성임피던스($Z_o$), 마이크로파 유효굴절률($N_{eff}$), 감쇠정수($a_o$)를 측정하여 그 결과를 이론치와 비교하였다. 전극두께가 11${\mu}m$이고, $SiO_2$ 완중박막을 식각한 전극에 대하여, RF 측정결과로부터 계산된 3dB 변조대역폭은 18GHz로 나타났다.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.77.2-77
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• 2000

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1352-1354
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• 1998

$LiNbO_3$ transistor showed relatively stable characteristic, low interface trap density, and large remanent polarization. This paper reports ferroelectric $LiNbO_3$ thin films grown directly on p-type Si(100) substrates by 13.56 MHz rf magnetron sputtering system for FRAM applications. To take advantage of low temperature requirement for growing films, we deposited $LiNbO_3$ films lower than $300 ^{\circ}C$. RTA(Rapid Thermal Anneal) treatment was performed for as-deposited films in an oxygen atmosphere at $600^{\circ}C$ for 60 sec. We learned from X-ray diffraction that the RTA annealed films were changed from amorphous to poly-crystalline $LiNbO_3$ which exhibited (012), (015), and (022) orientations. The I-V characteristics of $LiNbO_3$ films before and after anneal treatment showed that RTA improved the leakage current of films. The leakage current density of films decreased from $10^{-5}$ to $10^{-7} A/cm^2$ at room temperature measurement. Breakdown electric field of the films exhibited higher than 500 kV/cm. The C-V curves showed the clockwise hysteresis represents ferroelectric switching characteristics. From C-V curves, we calculated dielectric constant of thin film $LiNbO_3$ as 27.5 which is close to that of bulk value.

• 전자공학회논문지A
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• 제32A권7호
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• pp.94-103
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• 1995

Thin film acoustooptic beam deflector in proton-exchanged Y-cut LiNbO$_{3}$ was fabricated and measured. The planar waveguide was fabricated by using the proton-exchanged and annealing method in Y0cut LiNbO$_{3}$. Interdigital transducer for SAW(surface acoustic wave) was made by the laser lithography. Using above method, the thin film acoustooptic beam deflector was constructed. Its SAW wavelength was 20.mu.m at 174MHz center frequency. The interaction length between guided optical wave and SAW was 2.16mm. The measured 3dB bandwidth was 17MHz using He-Ne laser. And 70% diffraction efficiency was obtained at 970mW RF driving power.

• 대한전자공학회논문지SD
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• 제38권11호
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• pp.765-770
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• 2001

고온 급속 열처리시킨 LiNbO₃/AIN/Si(100) 구조를 이용하여 MFIS 소자를 제작하고, 비휘발성 메모리 동작 가능성을 확인하였다. 고유전율 AIN 박막 위에 Pt 전극을 증착시켜 제작한 MIS 구조에서 측정한 1MHz C-V 특성곡선에서는 히스테리시스가 전혀 없고 양호한 계면특성을 보였으며, 축적 영역으로부터 산출한 비유전율 값은 약 8 이었다. Pt/LiNbO₃/AIN/Si(100) 구조에서 측정한 1MHz C-V 특성의 축적영역에서 산출한 LiNbO₃ 박막의 비유전율 값은 약 23 이었으며, ±5 V의 바이어스 범위 내에서의 메모리 윈도우는 약 1.2 V이었다. 이 MFIS 구조에서의 게이트 누설전류밀도는 ±500 kV/cm의 전계 범위 내에서 10/sup -9/ A/㎠ 범위를 유지하였다. 500 kHz의 바이폴러 펄스를 인가하면서 측정한 피로특성은 10/sup 11/ cycle 까지 초기값을 거의 유지하는 우수한 특성을 보였다.