• JSTS:Journal of Semiconductor Technology and Science
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• 제8권1호
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• pp.51-65
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• 2008

The article presents the recent research development in polymer ferroelectric non-volatile memory. A brief overview is given of the history of ferroelectric memory and device architectures based on inorganic ferroelectric materials. Particular emphasis is made on device elements such as metal/ferroelectric/metal type capacitor, metal-ferroelectric-insulator-semiconductor (MFIS) and ferroelectric field effect transistor (FeFET) with ferroelectric poly(vinylidene fluoride) (PVDF) and its copolymers with trifluoroethylene (TrFE). In addition, various material and process issues for realization of polymer ferroelectric non-volatile memory are discussed, including the control of crystal polymorphs, film thickness, crystallization and crystal orientation and the unconventional patterning techniques.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.119-119
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• 2008

The electrical characteristics of Metal-Ferroelectric-Nitride-Oxide-Silicon (MFNOS) structure is studied and compared to the conventional Silicon-Oixde-Nitride-Oxide-Silicon (SONOS) capacitor. The ferroelectric blocking layer is SrBiNbO (SBN with Sr/Bi ratio 1-x/2+x) with the thickness of 200 nm and is fabricated by the RF sputter. The memory windows of MFNOS and SONOS capacitors with sweep voltage from +10 V to -10 V are 6.9 V and 5.9 V, respectively. The effect of ferroelectric blocking layer and charge trapping on the memory window was discussed. The retention of MFNOS capacitor also shows the 10-years and longer retention time than that of the SONOS capacitor. The better retention properties of the MFNOS capacitor may be attributed to the charge holding effect by the polarization of ferroelectric layer.

• 한국세라믹학회지
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• 제35권7호
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• pp.665-670
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• 1998

Ferroelectric anomaly in PbO-{{{{ { {B }_{2 }O }_{3 } }}-{{{{ {TiO }_{3 } }}-BaO glasses which is observed in DAT measurements was in-vestigated together with the effect of BaO content on the shift of Cuire temperature. The temperature where the ferroelectric anomaly apperars on cooling in DTA decreased in proportion with increasing BaO content,. For as-crystallized samples the ferroelectric anomaly was not observed on heating but on cooling whilist for powder samples leached chemically from the crystallized samples both endothermic and ex-otehrmic peaks were observed. This fact suggests that the appearance of the ferroelectric anomaly in DAT largely depends on glassy phases surrounding individual {{{{ {PbTiO }_{3 } }} crystals rather than effects of grain size and crystallinity.

• JSTS:Journal of Semiconductor Technology and Science
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• 제2권3호
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• pp.213-225
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• 2002

Metal-Ferroelectric- Insulator- Silicon (MFIS) structured field effect transistor (FET) device was fabricated and characterized. Important issues to realize ferroelectric gate field effect transistor device were summarized in three sections. The choice of interlayer dielectric was made in the consideration of device functionality and chemical reaction between ferroelectric materials and silicon surface during fabrication process. Also, various ferroelectric thin film materials were taken into account to meet desired memory window and process compatibility. Finally, MFIS structured FET device was fabricated and important characteristics were discussed. For feasible integration of current device as random access memory array cell address schemes were also suggested.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.174-174
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• 2008

Non-volatile memories using ferroelectric-gate field-effect transistors (Fe-FETs) with a metal/ferroelectric/semiconductor gate stack (MFS-FETs) make non-destructive read operation possible. In addition, they also have features such as high switching speed, non-volatility, radiation tolerance, and high density. However, the interface reaction between ferroelectric materials and Si substrates, i.e. generation of mobile ions and short retention, make it difficult to obtain a good ferroelectric/Si interface in an MFS-FET's gate. To overcome these difficulties, Fe-FETs with a metal/ferroelectric/insulator/semiconductor gate stack (MFIS-FETs) have been proposed, where insulator as a buffer layer is inserted between ferroelectric materials and Si substrates. We prepared $SrBi_2Ta_2O_9$ (SBT) film as a ferroelectric layer and $LaZrO_x$ (LZO) film as a buffer layer on p-type (100) silicon wafer for making the MFIS-FET devices. For definition of source and drain region, phosphosilicate glass (PSG) thin film was used as a doping source of phosphorus (P). Ultimately, the n-channel ferroelectric-gate FET using the SBT/LZO/Si Structure is fabricated. To examine the ferroelectric effect of the fabricated Fe-FETs, drain current ($I_d$) versus gate voltage ($V_g$) characteristics in logarithmic scale was measured. Also, drain current ($I_d$) versus drain voltage ($V_d$) characteristics of the fabricated SBT/LZO/Si MFIS-FETs was measured according to the gate voltage variation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.335-338
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• 1998

Ferroelectric Sr$_2$(Nb,Ta)$_2$O$_{7}$ (SNTO) thin films were prepared by chemical solution deposition processes. SNTO thin films were spin-coated on Pt/Ti/SiO$_2$/(100)Si substrates. After multiple coating, dried thin films were heat-treated for decomposition of residual organics and crystallization. B site-rich impurity phase, i.e. [Sr(Nb,Ta)$_2$O$_{6}$], was found after annealing, where its appearance was dependent on process temperature indicating the possible reaction with substrate. Dielectric and other relevant electrical properties were measured and the results showed a little possibility in ferroelectric gate random access memory devices.s.s.

• 한국정밀공학회지
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• 제22권2호
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• pp.120-125
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• 2005

Effect of transverse electric fields on fracture behavior in ferroelectric ceramics under purely electrical loading is investigated. It is shown that the shape and size of the domain switching zone depend strongly on the ratio of the transverse electric field to the coercive electric field as well as the direction of the applied electric field. Under small-scale conditions, the crack-tip mode I and II stress intensity factors induced by ferroelectric domain switching are numerically obtained. The crack kinking in ferroelectric ceramics is also discussed.

• Advances in nano research
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• 제14권4호
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• pp.329-334
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• 2023

Organic ferroelectric material found vast application in a verity of engineering and health technology fields. In the present study, we investigated the application of the deformable organic ferroelectric in motion measurement and improving performance in tennis players. Flexible ferroelectric material P(VDF-TrFE) could be used in wearable motion sensors in tennis player transferring velocity and acceleration data to collecting devises for analyzing the best pose and movements in tennis players to achieve best performances in terms of hitting ball and movement across the tennis court. In doing so, ferroelectric-based wearable sensors are used in four different locations on the player body to analyze the movement and also a sensor on the tennis ball to record the velocity and acceleration. In addition, poses of tennis players were analyzed to find out the best pose to achieve best acceleration and movement. The results indicated that organic ferroelectric-based sensors could be used effectively in sensing motion of tennis player which could be utilized in the optimization of posing and ball hitting in the real games.

• 대한전자공학회논문지
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• 제26권7호
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• pp.83-89
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• 1989

강유전성 $PbTiO_3$ 박막을 rf스터링으로 기판온도 $100{\sim}150^{\circ}C$에서 형성시켰다. 이 박막의 구조는 X선 회절결과 비정질 형태로 파이로클로어 구조를 갖고 있었다. 이 박막을 열에 의해 어닐링한 경우는 $550^{\circ}C$에서, 레이저의 주사로 어닐링한 경우는 레이저 출력이 50watts일때 가장 우수한 결정 구조를 구할 수 있었다. 집합에서의 계면 특성을 구하기 위하여 MFS(metal-ferroelectric-semiconductor)및 MFOS(metal-ferroelectric-oxide-semiconductor) 구조를 형성하여 C-V특성을 조사하였다. 이때 MFS보다 MFOS의 경우가 Si표면에 sputter에 의한 결함이 작음을 알 수 있었다.

• 한국정밀공학회지
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• 제20권11호
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• pp.142-149
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• 2003

Domain switching effect on crack growth in ferroelectric ceramics under combined electric and mechanical loading is investigated. The shape and size of the switching zone is shown to depend strongly on the relative magnitude between the applied electric field and stress field as well as on the ratio of the coercive electric field to the yield electric field. The toughening mechanism is thought to be ferroelectric domain switching leading to the development of a process zone around the crack. Crack-tip stress intensity factor induced by domain switching for the steady state crack growth is numerically obtained.