A Solid-State Thin-Film Electrolyte, Lithium Silicon Oxynitride, Deposited by using RF Sputtering for Thin-Film Batteries

Dan Na,Byeongjun Lee,Baeksang Yoon,Inseok Seo 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.9

In this study, a new lithium-silicon-oxynitride (LiSiON) solid-state thin-film electrolyte was investigated for the first time. The LiSiON thin-film electrolyte was deposited by using the RF sputtering technique. In order to compare the LiSiON thin-film electrolyte to lithium phosphorous oxynitride (LiPON), a conventional thin-film electrolyte, were deposited LiPON thin-film electrolytes by using RF sputtering. Surface morphologies and cross-sectional views of the thin-film electrolytes were characterized by using field emission scanning electron microscopy (FE-SEM). The thin-films showed smooth surfaces without any cracks and pinholes. The smooth surfaces are thought to decrease the interfacial resistance between the electrolyte and the electrodes. In addition, surface morphologies were characterized by using atomic force microscopy (AFM). The sputtering rates were calculated using the thicknesses of the thin-films, as obtained from cross-sectional views. The structural properties of the thin-films were characterized using X-ray diffraction (XRD). All thin-films showed amorphous properties compared to the target material which is a crystalline material. The ionic conductivity of the LiSiON thin-film was 2.47 × 10-6 (S/cm), which is slightly higher than that of a common thin-film electrolyte LiPON.

Boron Detection Technique in Silicon Thin Film Using Dynamic Time of Flight Secondary Ion Mass Spectrometry

( M. Abul Hossion ),( Brij M. Arora ) 한국질량분석학회 2021 Mass spectrometry letters Vol.12 No.1

The impurity concentration is a crucial parameter for semiconductor thin films. Evaluating the impurity distribution in silicon thin film is another challenge. In this study, we have investigated the doping concentration of boron in silicon thin film using time of flight secondary ion mass spectrometry in dynamic mode of operation. Boron doped silicon film was grown on i) p-type silicon wafer and ii) borosilicate glass using hot wire chemical vapor deposition technique for possible applications in optoelectronic devices. Using well-tuned SIMS measurement recipe, we have detected the boron counts 10¹~10⁴ along with the silicon matrix element. The secondary ion beam sputtering area, sputtering duration and mass analyser analysing duration were used as key variables for the tuning of the recipe. The quantitative analysis of counts to concentration conversion was done following standard relative sensitivity factor. The concentration of boron in silicon was determined 10¹⁷~10²¹ atoms/㎤. The technique will be useful for evaluating distributions of various dopants (arsenic, phosphorous, bismuth etc.) in silicon thin film efficiently.

2파장 펌프-프로브 기법을 이용한 질화규소 박막의 열물성 평가

김윤영,Kim, Yun Young 한국재료학회 2019 한국재료학회지 Vol.29 No.9

In the present study, the thermal conductivity of a silicon nitride($Si_3N_4$) thin-film is evaluated using the dual-wavelength pump-probe technique. A 100-nm thick $Si_3N_4$ film is deposited on a silicon (100) wafer using the radio frequency plasma enhanced chemical vapor deposition technique and film structural characteristics are observed using the X-ray reflectivity technique. The film's thermal conductivity is measured using a pump-probe setup powered by a femtosecond laser system of which pump-beam wavelength is frequency-doubled using a beta barium borate crystal. A multilayer transient heat conduction equation is numerically solved to quantify the film property. A finite difference method based on the Crank-Nicolson scheme is employed for the computation so that the experimental data can be curve-fitted. Results show that the thermal conductivity value of the film is lower than that of its bulk status by an order of magnitude. This investigation offers an effective way to evaluate thermophysical properties of nanoscale ceramic and dielectric materials with high temporal and spatial resolutions.

타원편광분광법 및 수소삼출법을 이용한 박막 실리콘의 증착온도 변화에 따른 미세구조 상관관계 연구

김가현 한국물리학회 2019 새물리 Vol.69 No.5

본 연구에서는 타원편광분광법 및 수소삼출법을 이용한 박막 실리콘 재료의 재료물성 분석결과를 다룬다. 비정질 실리콘 계열 박막 실리콘 재료는 결정질 실리콘과 다른 특징적 물성을 보이는데, 대표적으로재료의 밴드갭이 결정질 실리콘의 1.1 eV에 비해 광폭으로 1.7 eV 정도이며, 결정질 실리콘에 비해 높은흡광계수 및 직접천이 반도체와 같은 거동 등이 있다. 타원편광분광분석법은 시편에 조사된 빛의 편광상태변화를 관찰하는 기법으로 재료물성의 관점에서는 간접적인 분석법이다. 이를 재료에 대한 의미있는정보로 변환하기 위해서는 측정결과의 정확한 모델링이 필수적이다. 실리콘 박막의 물성 분석을 위해토크-로렌츠 분산모델(Tauc-Lorentz dispersion model)을 사용하였다. 타원편광분광법을 이용한 박막실리콘 재료의 측정결과를 토크-로렌츠 분산모델을 적용하여 분석하는 방법 및 수소삼출 실험결과와의비교를 통한 분산모델의 적정성 검증에 대한 논의를 다룬다. We analysed the material properties of thin-film silicon materials by using spectroscopic ellipsometry and hydrogen effusion. Hydrogenated amorphous silicon and the related thin film silicon material showed material properties significantly different from those of crystalline silicon, such as a wider band gap of about 1.7 eV, instead of the 1.1 eV in crystalline silicon, an elevated absorption coefficient, and characteristics of a direct bandgap. From a material point of view, an ellipsometry measurement is an indirect measurement because the result is usually given by a change in the polarization state of the probe light, so the ellipsometry measurement result must be transformed into meaningful parameters by modeling the measurement result. We used Tauc-Lorentz dispersion to model the ellipsometry measurement of the thin silicon film. In this paper, we discuss the modeling of spectroscopic ellipsometry data from thin-film silicon materials and the verification of the modeling result by using data from a complementary hydrogen effusion experiment

A Study on the Feasibility of Silicon Nitride Thin Film as Diffusion Barriers over IC Chip Packaging

Jo, Myung-Chan,Noh, Byeong-Il 한국공업화학회 2002 Journal of Industrial and Engineering Chemistry Vol.8 No.5

The feasibility of using Plasma-Enhanced Chemical Vapor Deposited (PECVD) silicon nitride thin films as diffusion barriers over metal bondpads, bonds, and bondwires in microelectronic packagings was investigated. Films between 550 to 5000 Å were almost impervious to salt solution over 36 h. Film over a micron cracked spontaneously from internal stresses. Film thickness measurement under a 1 mil bondwire over a flat silicon substrate by a stylus profilometer showed that the film began to get significantly thinner starting over four wire diameters away from the center of the bond. Salt immersion test indicated that the failure mechanism was corrosion of bondpad metallization starting under the stitch bond due to incomplete coverage of the silicon nitride film. Thermal shock cracked the films and caused severe corrosion on the metal bonding areas as evidenced by hydrogen evolution during salt immersion testing. The results showed that PECVD silicon nitride thin film can be potential protective films over metal areas in microelectronic assemblies, by optimizing the deposition conditions for more conformal coating in the occluded cavity under the stitch bond and increased resistance to thermal stress-induced cracking.

Fabrication and Characterization of Ion-Doped p-Type Nanocrystalline Silicon Thin-Film Transistors

Yassine Djeridane,Pere Roca i Cabarrocas,김가현,김세환,배정호,정준영,장진 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.1

We report on the fabrication of coplanar p-channel nanocrystalline silicon thin-film transistors (nc-Si TFT) by using conventional boron ion doping. p-channel TFTs are necessary to implement complementary metal-oxide-semiconductor (CMOS) circuits with low power consumption, but amorphous silicon and polycrystalline silicon p-channel TFTs both have drawbacks, such as low hole mobility, high cost and poor uniformity. On the other hand, nanocrystalline silicon shows many merits, encouraging its use in CMOS circuits such as reasonable carrier mobility, high uniformity and ease of processing, despite these advantages, very few studies of p-type nanocrystalline silicon TFTs have been performed and there have been no documented efforts to adopt an ion-doped coplanar structure or to optimize its fabrication process. The TFTs presented herein have been fabricated using a conventional ion-doping process and show reasonably optimized characteristics, so the result demonstrated in this paper can be immediately adopted in a large-area, industrial system with little adjustment. Moreover, it is quite a new concept to use nanocrystalline silicon thin films for coplanar p-channel TFTs. The nanocrystalline silicon thin-films used in this work were grown on glass substrates at a low substrate temperature of 200 ℃ by using a SiF<SUB>4</SUB>/H<SUB>2</SUB>/Ar mixture. The TFTs that resulted from these films exhibited a field-effect mobility of 1.52 cm<SUP>2</SUP>/Vs, a gate voltage swing of 1.1 V/dec, an on/off ratio in excess of 10<SUP>6</SUP> and a threshold voltage of −6.28 V.

유기 나노 보강층을 활용한 유연 디스플레이용 절연막의 기계적 물성 평가

오승진,마부수,양찬희,송명,김택수,Oh, Seung Jin,Ma, Boo Soo,Yang, Chanhee,Song, Myoung,Kim, Taek-Soo 한국마이크로전자및패키징학회 2021 마이크로전자 및 패키징학회지 Vol.28 No.3

최근 유연 디스플레이에 관한 대중의 관심이 증대됨에 따라 롤러블(rollable), 폴더블(foldable) 디스플레이와 같은 우수한 폼 팩터(form factor)를 지닌 차세대 유연(flexible) 디스플레이가 주목받고 있다. 유연 디스플레이의 기계적 신뢰성 확보 측면에서, 내부 절연막으로 활용되는 실리콘 질화물(SiN_x) 박막은 구동 중 발생하는 응력에 매우 취약하므로 기계적 물성을 정확히 파악하여 파손을 예측하고 패널의 전기적 단락을 방지하는 것이 중요하다. 본 논문에서는, ~130 nm, ~320 nm 두께의 SiN_x 박막 박막 상부에 ~190 nm 두께의 유기 나노 보강층(PMMA, PS, P3HT)을 코팅하여 이중층 구조로 인장함으로써 매우 취성한 SiN_x 박막의 탄성 계수와 인장 강도 및 연신율을 측정하는 데 성공하였다. 챔버 압력 및 증착 파워를 조절한 공정 조건(A: 1250 mTorr, 450 W/B: 1000 mTorr, 600 W/C: 750 mTorr, 700 W)을 통해 제작된 ~130 nm SiN_x 의 탄성계수는 A: 76.6±3.5, B: 85.8±4.6, C: 117.4±6.5 GPa로, ~320 nm SiN_x는 A: 100.1±12.9, B: 117.9±9.7, C: 159.6 GPa로 측정되었다. 결과적으로, 동일 공정 조건 하에서 SiN_x 박막의 두께가 증가할수록 탄성 계수가 증가하는 경향을 확인하였으며, 유기 나노 보강층을 활용한 인장 시험법은 파손되기 쉬운 취성 박막의 기계적 물성을 높은 정밀도로 측정하는 데 효과적이었다. 본 연구에서 개발된 방법은, 취약한 디스플레이용 박막의 정량적인 기계적 물성 파악을 가능케하여 강건한 롤러블, 폴더블 디스플레이의 설계에 이바지할 수 있을 것으로 기대한다. Recently, rollable and foldable displays are attracting great attention in the flexible display market due to their excellent form factor. To predict and prevent the mechanical failure of the display panels, it is essential to accurately understand the mechanical properties of brittle SiN_x thin films, which have been used as an insulating film in flexible displays. In this study, tensile properties of the ~130 nm- and ~320 nm-thick SiN_x thin films were successfully measured by coating a ~190 nm-thick organic nano-support-layer (PMMA, PS, P3HT) on the fragile SiN_x thin films and stretching the films as a bilayer state. Young's modulus values of the ~130 nm and ~320 nm SiN_x thin films fabricated through the controlled chamber pressure and deposition power (A: 1250 mTorr, 450 W/B: 1000 mTorr, 600 W/C: 750 mTorr, 700 W) were calculated as A: 76.6±3.5, B: 85.8±4.6, C: 117.4±6.5 GPa and A: 100.1±12.9, B: 117.9±9.7, C: 159.6 GPa, respectively. As a result, Young's modulus of ~320 nm SiN_x thin films fabricated through the same deposition condition increased compared to the ~130 nm SiN_x thin films. The tensile testing method using the organic nano-support-layer was effective in the precise measurement of the mechanical properties of the brittle thin films. The method developed in this study can contribute to the robust design of the rollable and foldable displays by enabling quantitative measurement of mechanical properties of fragile thin films for flexible displays.

Oxidation behavior of amorphous boron carbide–silicon carbide nano-multilayer thin films

Bae, K.-E.,Chae, K.-W.,Park, J.-K.,Lee, W.-S.,Baik, Y.-J. Elsevier 2015 Surface & Coatings Technology Vol.276 No.-

<P><B>Abstract</B></P> <P>This experiment studied the effect of nano-multilayer structures of boron carbide film with silicon carbide (SiC) layers on oxidation behavior and hardness. The multilayer films were deposited at 450°C using an unbalanced dual-gun magnetron sputtering system with stoichiometric B<SUB>4</SUB>C and SiC targets. The period of the multilayer system (the thickness of one pair of boron carbide and SiC layers) with a constant film thickness was varied between 2.3nm and 22.1nm. The structures of these multilayer thin films were amorphous irrespective of the period. A remarkable hardness enhancement, frequently observed in crystalline nano-multilayer thin film systems, did not appear. The maximum hardness of the multilayer thin film was measured to be about 36GPa, similar to that of the monolithic boron carbide film deposited under the same condition. Oxidation was, however, greatly reduced by the insertion of the SiC layers. Oxidation was rarely observed at temperatures up to 1200°C, the maximum experimental temperature, whereas significant oxidation was observed at around 700°C in the case of the boron carbide monolithic film.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Investigation of oxidation behavior of silicon carbide - boron carbide nanomultilayers </LI> <LI> Significant reduction of oxidation of BC films by SiC layer insertion up to 1200°C </LI> <LI> Negligible decrease of the hardness of the film caused by the multilayer formation </LI> <LI> BC/SiC nanomultilayer coating as a candidate for cutting tool application used especially at high temperature </LI> </UL> </P>

Using the light scattering properties of multi-textured AZO films on inverted hemisphere textured glass surface morphologies to improve the efficiency of silicon thin film solar cells

Hussain, Shahzada Qamar,Le, Anh Huy Tuan,Mallem, Kumar,Park, Hyeongsik,Ju, Minkyu,Kim, Yongjun,Cho, Jaehyun,Park, Jinjoo,Kim, Youngkuk,Yi, Junsin Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.447 No.-

<P><B>Abstract</B></P> <P>We report the light scattering characteristics of multi-textured aluminum-doped zinc oxide (AZO) thin films with high optical transmittance, haze ratio and step coverage for amorphous silicon thin film solar cells (a-Si TFSCs). Multi-textured AZO films were deposited on inverted hemisphere textured (IHT) glass surface morphologies. Multi-textured process was used to create modulated surface morphologies with micro and nano-features useful for the light scattering in visible as well as near-infrared wavelength region. Highly transparent IHT glass surface morphologies with high haze ratio were prepared by wet chemical etching of periodic glass substrates. Total transmittance of the IHT glass substrates showed higher average values (91.38–93.40%) as compared to that of bare glass (90.94%) in the visible wavelength region due to lower reflectance. Multi-textured AZO films showed higher rms roughness 100.479 nm, optical transmittance 82.60% and haze ratio 75.09% in the visible wavelength region. X-ray photoelectron spectroscopic analysis of multi-textured AZO thin films was used to study the atomic compositions and chemical binding states. Multi-textured AZO films with high transmittance and haze ratio were used as front transparent conductive oxide layers for the fabrication of a-Si TFSCs using an absorber layer thickness of 400 nm. Multi-textured AZO films deposited on the optimal textured glass surface morphologies yield the maximum performance of a-Si TFSCs as; V<SUB>oc</SUB> = 871 mV, J<SUB>sc</SUB> = 16.55 mA/cm<SUP>2</SUP>, FF = 66.6% and η = 9.61%. An enhancement of photocurrent was noticed from 15.64 to 16.55 mA/cm<SUP>2</SUP> for the a-Si TFSCs deposited on as deposit AZO to optimal textured AZO films.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Micro-featured IHT glass surfaces with high transmittance, haze ratio were prepared. </LI> <LI> Multi-textured AZO films were deposited on IHT glass surface morphologies. </LI> <LI> XPS analysis of AZO films revealed Zn 2p, O 1s and C 1s as the dominating peaks. </LI> <LI> Increase in J<SUB>sc</SUB> upto 16.55 mA/cm<SUP>2</SUP> was related to light scattering in vis-NIR region. </LI> <LI> We propose multi-textured AZO films for future high efficiency silicon TFSCs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Mobility Enhancement in Polycrystalline Silicon Thin Film Transistors due to the Dehydrogenation Mechanism

Seok Ryoul Lee,Sang-Yun Sung,Kyong Taik Lee,Seong Gook Cho,Ho Seong Lee 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.9

We investigated the mechanism of mobility enhancement after the dehydrogenation process in polycrystalline silicon (poly-Si) thin films. The dehydrogenation process was performed by using an in-situ CVD chamber in a N2 ambient or an ex-situ furnace in air ambient. We observed that the dehydrogenated poly-Si in a N2 ambient had a lower oxygen concentration than the dehydrogenated poly-Si annealed in an air ambient. The in-situ dehydrogenation increased the (111) preferred orientation of poly-Si and reduced the oxygen concentration in poly-Si thin films, leading to a reduction of the trap density near the valence band. This phenomenon gave rise to an increase of the field-effect mobility of the poly-Si thin film transistor.