초고집적소자의 커패시터용 PZT 박막의 특성

마재평 호남대학교 정보통신연구소 1997 정보통신연구 Vol.6 No.-

초고집적소자의 커패시터용 PZT 박막의 형성 및 특성을 살펴보았다. Pt/Ti/Si기판 위에서 RF magnetron sputtering 방법으로 PZT 박막을 증착하였다. 후속 annealing은 furnace 및 RTA로 550에서 750도 사이에서 시행하였다. 상 형성, 막막의 조성 그리고 계면 반응 등을 XRD, XPS과 RBS 등으로 각각 조사하였고 I-V 및 C-V 특성은 각각 HP4145B와 HP4194A로 측정하였다. 후속 annealing때 Ti층의 상부는 바깥쪽으로부터의 산소 확산에 의해 Ti-oxide로 변화하였고 Ti층의 하부는 Pt이 확산해 들어와 silicide를 형성하였다. Ti-oxide의 형성은 PZT의 성장 방향에 영향을 주었다. RTA로 후속 annealing할 때 얇은 Pt층은 산소 확산을 억제하지 못했으나 1000Å으로 두껍게 입힌 Pt 층은 효과적으로 억제하였다. RTA 처리한 경우가 보다 좋은 강유전특성을 나타냈는데, 이때 누설전류는 3.35㎂/㎠였으며 breakdown voltage는 0.63MV/cm로 나타났다. The formations and properties of PZT thin films were investigated to survey applicability for ULSI's capacitor. PZT films were deposited by RF magnetron sputtering on Pt/Ti/Si substrates followed by furnace-and rapid thermal annealing at 550℃ to 750℃. Phase formations, film compositions and interface reactions were analyzed by XRD, XPS and RBS, respectively. I-V and C-V characteristics were investigated by HP4145B and HP4194A. The upper Ti layer is transformed into Ti-oxide by oxygen diffusion and lower Ti layer into silicide with in-diffused Pt for post-annealing. The formation of Ti-oxide layer seems to affect the orientation of the PZT layer. During rapid thermal annealing process, Pt(250Å) layer could not prevented oxygen diffusion but thicker Pt(1000Å) did, effectively. Rapid-thermal-annealed film shows better ferroelectric and electrical properties with a leakage current of 3.35 ㎂/㎠, breakdown voltage of 0.63 MV/cm.

각 층에 따른 염료감응형 태양전지의 특성 개선 - I (-상부전극을 중심으로)

마재평,박치선,Mah, Jae-Pyung,Park, Chi-Sun 한국반도체디스플레이기술학회 2011 반도체디스플레이기술학회지 Vol.10 No.2

Photovoltaic effect is confirmed in DSSC fabricated under the common conditions. In upper electrodes, validity of ZnO as new TCO material was investigated and an improvement of characteristics in DSSC was tried by control of process conditions at semiconductive powder layer. ZnO thin film showed very high resistivity, therefore efficiency of solar cell was lower than that of conventional ITO-related material. DSSC characteristics was able to improve by thin blocking layer doposited between the TCO and semiconductor layer.

저전압용 ZnO 바리스터계의 비음성에 대한 Bi2O3의 영향

마재평,박치선,백수현 대한전자공학회 1985 대한전자공학회 학술대회 Vol.1985 No.1

천이금속-산화물 양에 따른 ZnP 바리스터 특성변화 ( ZnO Varistor Property Changes By Transition Metal-Oxide Amount )

마재평,박치선,백수현 대한전자공학회 1985 대한전자공학회 학술대회 Vol.1985 No.1

저전압용 ZnO varistor 계의 nonohmic 특성에 대한 Bi₂O₃의 영향

馬在坪 호남대학교 1991 호남대학교 학술논문집 Vol.12 No.2

Two systems orienting low voltage varistor were investigated by electrical and mocrostructural methods. Zn, Bi, Co, Mn-oxide system has so relatively large grain size that this showed low breakdown voltage, hence in the development of low voltage varistor this system can be used it as basic system. Its nonlinear exponents were 20 or more, and nonlinear resistances were 40 V/mm or less, but real breakdown voltage in Ⅴ-Ⅰ plotting was about 30 V/mm. Adequate Bi₂O₃ amount is about 1.0mol%.

단결정 Si 기판상에서 PZT의 상 형성

마재평 호남대학교 2000 호남대학교 학술논문집 Vol.21 No.2

The phase formations of PZT thin films sputtered on the single Si substrate were investigated to establish the base in this field. Perovskite phase was not shown in PZT films furnace-annealed, and lead-oxide,-silicates were formed. This phenomena were due to the severe dissociation and/or diffusion of PZT's components and Si. PZT thin films were undergone by too high heat-input by furnace-annealing and their polarization characteristics were degradaded, so it was proposed that the substrate for diffusion-barrier and the RTA as post-annealing were needed in the formation of ferroelectric PZT films.

In-situ 공정으로 형성시킨 PZT 박막의 특성

마재평 호남대학교 산업기술연구소 1997 산업기술연구논문집 Vol.5 No.-

초고집적반도체소자의 커패시터용 PZT 박막을 기판온도와 gas 주입량을 달리하며 RF magnetron sputtering 방법으로 Pt/Ti/SiO₂/Si 기판상에 in-situ 공정으로 제조하였다. 상 형성, 박막의 조성, 계면 반응 그리고 I-V특성 등을 XRD, SIMS, HP4145B 그리고 HP4194A 등으로 조사하였다. 기판 온도를 600℃로 하고 gas를 O₂/Ar=1/9로 주입했을 때, preferred orientation을 나타내는 안정한 perovskite 상이 형성되고 계면이 안정되게 유지되어 좋은 전기적 특성을 나타냈다. 이때 누설전류는 ?? order에 이르렀고 유전상수도 960으로 매우 큰 값을 보였다. 이와같은 조건에서 in-situ 공정으로 제조한 PZT 박막은 탁월한 전기적 특성을 지녀 기가 DRAM급 이상의 차세대 초고집적 반도체에의 적용 가능성이 큼을 알 수 있었다. By in-situ process under the various substrate temperatures and ratios of introducing gases, PZT thin films for ULSI's capacitor were deposited on the Pt/Ti/SiO₂/Si substrate in the RF magnetron sputtering system. Phase formations, film compositions, interface reactions, and I-V and C-V characteristics were analyzed by XRD, SIMS,HP4145B and HP4194A. As results, the 200 nm PZT thin film prepared at 600℃ in the gas ratio of O₂/Ar=1/9 formed as stable perovskite structure with preferred orientation. Under the condition, it keeped stable intergace and good electrical properties. For that condition, leakage current diensity was ??, dielectric constant of 960. PZT thin films fabricated by under those conditions by in-situ process have good dielectric properties so that the films will bi able to be applied to over giga order DRAM.

2단계 sputtering으로 제조한 PZT 박막의 특성

마재평 호남대학교 1997 호남대학교 학술논문집 Vol.18 No.4

PZT thin films were fabricated on Pt/Ti/SiO₂/Si substrates by 2-step sputtering. In-situ process was used to form a ferroelectric perobskite structure and a higher density film. In the case of the samples that were deposited for 10 minute at room temperature and for 110 minute at 600℃, dielectric constant is 900 or more and breakdown voltage is 23V. Especially, the leakage current of the samples containing amorphous PZT layer was decreased. Covering effect of the amorphous layer formed at room temperature is excellent, and, therefore, the dielectric properties of the PZT films containing thin amorphous layer were improved by 2-step sputtering.

초고집적회로의 커패시터용 PZT박막의 입열 조건에 따른 유전특성 -1- 비정질 PZT를 사용한 PZT 박막의 누설전류 개선에 관한 연구

마재평,백수현,황유상 대한전자공학회 1995 전자공학회논문지-A Vol.32 No.12

To improve the leakage current, we developed two step sputtering method where PZT thin film in first deposited at room temperature followed by 600.deg. C deposition. The method used an amorphous PZT layer deposited at room temperature to keep a stable interface during sputtering at high temperature. PZT thin films were deposited on Pt/Ti/SiO$_{2}$/Si substrate at room temperature and 600.deg. C sequentially. The effect of the layer deposited at room temperature was investigated with regard to I-V characteristics and P-E hysteresis loop. In the case of the sample with the layer deposited at room temperature, both leakage current and dielectric constant were decreased. The thicker the layer deposited at room temperature was, the lower dielectric constant was. However, leakage current was indepenent of the variation of the thickness ratio. The sample with 200$\AA$ of the layer deposited at room temperature showed the most promising results in both dielectric constant and leakage current.

초고집적반도체의 커패시터용 강유전 박막의 전기적 특성 개선

마재평,박삼규,Mah Jae-Pyung,Park Sam-Gyu 한국마이크로전자및패키징학회 2004 마이크로전자 및 패키징학회지 Vol.11 No.3

PBT thin films were formed by rf-magnetron sputtering on $Pt/Ti/SiO_2/Si$ substrate. Bulk-PZT target containing $5\%$-excess PbO was used. After PZT thin films had been deposited at room temperature, remaining portion of the thin film was formed by in-situ process. The ferroelectric perovskite phase was formed at $650^{\circ}C$. The leakage current property was improved dramatically by 2-step sputtering, and in the sample containing optimum thickness of room temp.-layer very low leakage current of $2{\times}10^{-7}A/cm^2$ was shown. As a result of the investigation on the leakage current mechanism, the electrical conduction mechanism in all PZT thin films formed by several conditions was confirmed as bulk-limited mechanism. PZT 박막을 rf-마그네트론 스퍼터링으로 $Pt/Ti/SiO_2/Si$ 기판 위에 형성시켰다. $5\%$ 과잉 PbO 를 포함한 bulk PZT 타겟을 사용하였다. 상온에서 PZT 박막을 얇게 입힌 후 나머지 두께를 $650^{\circ}C$에서 in-situ 방법으로 형성시켰다. 강유전 특성을 갖는 PZT 상은 $650^{\circ}C$에서 형성되었다. 2단계 스퍼터링에 의해 누설전류 특성을 크게 증진시킬 수 있었고, 적절한 두께의 상온층을 포함시킨 경우 $2{\times}10^{-7}A/cm^2$의 매우 작은 누설전류를 나타냈다. 누설전류 기구에 대한 조사 결과, 여러 조건에서 제조된 PZT 박막의 전기전도는 모두 bulk-limit 기구에 의한 것임을 알 수 있었다.