• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.689-689
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• 2013

Atomic layer deposition (ALD)에 의한 알루미늄 산화 막(Al2O3)은 고효율 결정질 실리콘 태양전지를 위한 우수한 표면 패시베이션 특성을 제공한다. 알루미늄 산화막는 고정적인 음전하를 가지고 있기 때문에 p-형 실리콘 태양 전지 후면은 전계에 의한 우수한 패시베이션 효과를 형성한다. 그러나, ALD 방식으로 증착된 알루미늄 산화막은 매우 긴 공정 시간을 필요로 하기 때문에 기존의 실리콘 태양 전지 공정에 적용하기가 어렵다. 본 논문에서는 알루미늄 산화막 형성에서 공정 시간을 줄이기 위해 Plasma assisted atomic layer deposition (PA-ALD) 방식을 적용했다. PA-ALD 기술은 trimethylaluminum (TMA)과 O2를 사용하여 기판 표면에 알루미늄 산화막을 증착하는 것으로 ALD 방식과 유사하지만, O2 플라즈마를 사용함으로써 증착 속도를 향상시킬 수 있다. 이는 좋은 패시베이션 특성을 가지는 알루미늄 산화막을 실리콘 태양전지양산 공정에 적용할 수 있는 가능성을 제시한다. PA-ALD 방식에 의한 알루미늄 산화막의 패시베이션 특성을 최적화하기 위해서 증착 후 열처리 조건에 대한 연구도 수행하였다. 막증착률이 1.1${\AA}$/cycle인 Al2O3층의 두께 변화에 따른 특성을 최적화하기 위해 공정 온도를 $250^{\circ}C$ 고정하고, 열처리 온도와 시간을 가변하였으며 유효 반송자수명을 측정하여 알루미늄 산화막의 패시베이션 특성을 확인했다.

• Journal of the Semiconductor & Display Technology
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• v.4 no.2 s.11
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• pp.39-43
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• 2005

In the study, in order to deposit TaN thin film for diffusion barrier and bottom electrode we made the Plasma Assisted ALD equipment and confirmed the electrical characteristics of TaN thin films grown PAALD method. Plasma Assisted ALD equipment depositing TaN thin film using PEMAT(pentakis(ethylmethlyamino) tantalum) precursor and NH3 reaction gas is shown that TaN thin film deposited high density and amorphous phase with XRD measurement. The degree of diffusion and reaction taking place in Cu/TaN (deposited using 150W PAALD)/$SiO_{2}$/Si systems with increasing annealing temperature was estimated for MOS capacitor property and the $SiO_{2}$, (600${\AA}$)/Si system surface analysis by C-V measurement and secondary ion material spectrometer (SIMS) after Cu/TaN/$SiO_{2}$ (400 ${\AA}$) layer etching. TaN thin film deposited PAALD method diffusion barrier have a good diffusion barrier property up to 500$^{\circ}C$.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.234.2-234.2
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• 2014

Organic light emitting diode (OLED) is considered as the next generation flat panel displays due to its advantages of low power consumption, fast response time, broad viewing angle and flexibility. For the flexible application, it is essential to develop thin film encapsulation (TFE) to protect oxidation of organic materials from oxidative species such as oxygen and water vapor [1]. In many TFE research, the inorganic film by atomic layer deposition (ALD) process demonstrated a good barrier property. However, extremely low throughput of ALD process is considered as a major weakness for industrial application. Recently, there has been developed a high throughput ALD, called 'spatial ALD' [2]. In spatial ALD, the precursors and reactant gases are supplied continuously in same chamber, but they are separated physically using a purge gas streams to prevent mixing of the precursors and reactant gases. In this study, the $Al_2O_3$ thin film was deposited by spatial ALD process. We characterized various process variables in the spatial ALD such as temperature, scanning speed, and chemical compositions. Water vapor transmission rate (WVTR) was determined by calcium resistance test and less than $10-^3g/m^2{\cdot}day$ was achieved. The samples were analyzed by x-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM).

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.139-145
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• 2005

In the study, in order to deposit TaN thin film using diffusion barrier and bottom electrode we made the Plasma Assisted ALD equipment and confirmed the electrical characteristic of TaN thin films deposited PAALD method, PAALD equipment depositing TaN thin film using PEMAT(pentakis(ethylmethlyamlno) tantalum) Precursor and $NH_3$ reaction gas is aware that TaN thin film deposited of high density and amorphous phase with XRD measurement The degree of diffusion and react ion taking place in Cu/TaN(deposited using 150 W PAALD)/$SiO_2$/Si systems with increasing annealing temperature was estimated from MOS capacitor property and the $SiO_2(600\;\AA)$/Si system surface analysis by C-V measurement and secondary ion material spectrometer(SIMS) after Cu/TaN/$SiO_2(400\;\AA)$ system etching. TaN thin film deposited PAALD method diffusion barrier have a good diffusion barrier property up to $500^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.10
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• pp.754-759
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• 2013

Aluminum oxide($Al_2O_3$) film deposited by atomic layer deposition (ALD) is known to supply excellent surface passivation properties on crystalline Si surfaces. Since $Al_2O_3$ has fixed negative charge, it forms effective surface passivation by field effect passivation on the rear side in p-type silicon solar cell. However, $Al_2O_3$ layer formed by ALD process needs very long process time, which is not applicable in mass production of silicon solar cells. In this paper, plasma-assisted ALD(PA-ALD) was applied to form $Al_2O_3$ to reduce the process time. $Al_2O_3$ synthesized by ALD on c-Si (100) wafers contains a very thin interfacial $SiO_2$ layer, which was confirmed by FTIR and TEM. To improve passivation quality of $Al_2O_3$ layer, the deposition temperature was changed in range of $150{\sim}350^{\circ}C$, then the annealing temperature and time were varied. As a result, the silicon wafer with aluminum oxide film formed in $250^{\circ}C$, $400^{\circ}C$ and 10 min for the deposition temperature, the annealing temperature and time, respectively, showed the best lifetime of 1.6ms. We also observed blistering with nanometer size during firing of $Al_2O_3$ deposited on p-type silicon.

• Journal of the Korean Vacuum Society
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• v.18 no.4
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• pp.296-301
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• 2009

An inductively coupled plasma assisted atomic layer deposition(ICP-ALD) system has been constructed for the deposition of ZnO thin films, and various experiments of ZnO thin films on p-type Si(100) substrates have been carried out to find the self-limiting reaction conditions for the ICP-ALD system under non-plasma circumstances. Diethyl zinc[$Zn(C_2H_5)_2$, DEZn] was used as the zinc precursor, $H_2O$ as the oxidant, and Ar as the carrier and purge gas. At the substrate temperature of $150^{\circ}C$, atomic layer deposition conditions based on self-limiting surface reaction were successfully obtained by series of experiments through the variation of exposure times for DEZn, $H_2O$, and Ar. ZnO deposition was repeated at different substrate temperatures of $90{\sim}210^{\circ}C$. As a result, the thermal process window(ALD window) for ZnO thin films was observed to be $110{\sim}190^{\circ}C$ and the average growth rate was measured to be constant of 0.29 nm/cycle. Properties of the film's microstructure and composition(Zn, O, etc.) were also studied. As the substrate temperature increases, the crystallinity was improved and ZnO(002) peak became dominant. The films deposited at all temperatures were high purity, and the films deposited at high temperatures had the composition ratio between Zn and O closer to one of a stable hexagonal wurtzite structure.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.246-246
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• 2013

Atomic layer deposition (ALD)에 의해 증착된 알루미늄 산화막($Al_2O_3$)은 고효율 결정질 실리콘 태양전지를 위한 우수한 패시베이션 효과를 보인다. $Al_2O_3$은 고정 음전하를 가지고 있기때문에 p-형 태양전지 후면에서 field effect passivation에 의한 효과적인 표면 패시베이션을 형성한다. 하지만 ALD에 의한 $Al_2O_3$ 증착은 긴 공정시간이 필요하다. 이는 기존의 태양전지 산업에 적합하지 않다. 본 논문에서는 공정 시간의 단축을 위해 plasma-assisted atomic layer deposition (PA-ALD) 기술을 사용함으로서 $Al_2O_3$을 증착했다. PA-ALD 기술은 trimethyaluminum (TMA)와 plasma 분위기에서의 $O_2$ 가스를 사용하여 표면 반응을 한다. $Al_2O_3$ 층의 특성을 최적화하기 위해 증착 온도를 $150{\sim}250^{\circ}C$의 범위에서 가변하고, 열처리 온도와 시간을 변화하였다. 결과적으로, 실리콘 웨이퍼를 이용하여 $1250^{\circ}C$의 공정온도에서 증착한 $Al_2O_3$은 $400^{\circ}C$에서 10분 동안의 열처리 온도와 시간에서 1,610 ${\mu}s$의 최고의 유효 반송자 수명을 보였다.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.05a
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• pp.106-111
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• 2003

Tantalum nitride(TaN) films were deposited by atomic layer deposition(ALD) and plasma assisted atomic layer deposition(PAALD). The deposition of the TaN thin film has been performed using pentakis (ethylmethlyamino) tantalum (PEMAT) and ammonia($NH_3$) as precursors at temperature of $250^{\circ}C$, where the temperature was proven to be ALD window for TaN deposition from our previous experiments. The PAALD deposited TaN film shows better physical properties than thermal ALD deposited TaN film, due to its higher density$(~11.59 g/\textrm{cm}^3$) and lower carbon(~ 3 atomic %) and oxygen(~ 4 atomic %) concentration of impurities.

• Journal of the Semiconductor & Display Technology
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• v.6 no.3
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• pp.19-23
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• 2007

The NiSi is very promising candidate for the metallization in 45 nm CMOS process such as FUSI(fully silicided) gate and source/drain contact because it exhibits non-size dependent resistance, low silicon consumption and mid-gap workfunction. Ni film was first deposited by using ALD (atomic layer deposition) technique with Bis-Ni precursor and $H_2$ reactant gas at $220^{\circ}C$ with deposition rate of $1.25\;{\AA}/cycle$. The as-deposited Ni film exhibited a sheet resistance of $5\;{\Omega}/{\square}$. RTP (repaid thermal process) was then performed by varying temperature from $400^{\circ}C$ to $900^{\circ}C$ in $N_2$ ambient for the formation of NiSi. The process temperature window for the formation of low-resistance NiSi was estimated from $600^{\circ}C$ to $800^{\circ}C$ and from $700^{\circ}C$ to $800^{\circ}C$ with and without Ti capping layer. The respective sheet resistance of the films was changed to $2.5\;{\Omega}/{\square}$ and $3\;{\Omega}/{\square}$ after silicidation. This is because Ti capping layer increases reaction between Ni and Si and suppresses the oxidation and impurity incorporation into Ni film during silicidation process. The NiSi films were treated by additional thermal stress in a resistively heated furnace for test of thermal stability, showing that the film heat-treated at $800^{\circ}C$ was more stable than that at $700^{\circ}C$ due to better crystallinity.

• Journal of the Semiconductor & Display Technology
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• v.2 no.2
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• pp.5-8
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• 2003

In this study, as Cu diffusion barrier, tantalum nitrides were successfully deposited on Si(100) substrate and $SiO_2$ by plasma assisted atomic layer deposition(PAALD) and thermal ALD, using pentakis (ethylmethlyamino) tantalum (PEMAT) and NH$_3$ as precursors. The TaN films were deposited at $250^{\circ}C$ by both method. The growth rates of TaN films were 0.8${\AA}$/cycle for PAALD and 0.75${\AA}$/cycle for thermal ALD. TaN films by PAALD showed good surface morphology and excellent step coverage for the trench with an aspect ratio of h/w -1.8:0.12 mm but TaN films by thermal ALD showed bad step coverage for the same trench. The density for PAALD TaN was 11g/cmand one for thermal ALD TaN was 8.3g/$cm^3$. TaN films had 3 atomic % carbon impurity and 4 atomic % oxygen impurity for PAALD and 12 atomic % carbon impurity and 9 atomic % oxygen impurity for thermal ALD. The barrier failure for Cu(200 nm)/TaN(10 nm)/$SiO_2$(85 nm)/ Si structure was shown at temperature above $700^{\circ}C$ by XRD, Cu etch pit analysis.