• Journal of the Microelectronics and Packaging Society
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• v.15 no.4
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• pp.25-29
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• 2008

Reliability and performance in metal gate/high-k device with multiple gate dielectrics were investigated. MOSFETs with a thin $HfSiO_x$ layer on a thermal Si02 dielectric as gate dielectrics exhibit excellent mobility and low interface trap density. However, the distribution of threshold voltages of $HfSiO_x/SiO_2$ stack devices were wider than those of $SiO_2$ and $HfSiO_x$ single layer devices due to the penetration of Hf and/or intermixing of $HfSiO_x$ with underlying $SiO_2$. The results of TZDB and SILC characteristics suggested that a certain portion of $HfSiO_x$ layer reacted with the underlying thick $SiO_2$ layer, which in turn affected the reliability characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.163.2-163.2
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• 2014

We report catalytic decomposition of few-layer graphene on an $Au/SiO_x/Si$ surface wherein oxygen is supplied by dissociation of the native $SiO_x$ layer at a relatively low temperature of $400^{\circ}C$. The detailed chemical evolution of the graphene covered $SiO_x/Si$ surface with and without gold during the catalytic process is investigated using a spatially resolved photoelectron emission method. The oxygen atoms from the native $SiO_x$ layer activate the gold-mediated catalytic decomposition of the entire graphene layer, resulting in the formation of direct contact between the Au and the Si substrate. The notably low contact resistivity found in this system suggests that the catalytic depletion of a $SiO_x$ layer could realize a new way to micromanufacture high-quality electrical contact.

• Journal of the Korean institute of surface engineering
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• v.50 no.5
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• pp.345-351
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• 2017

A double-layered anti-reflective coating with hydrophilic/abrasion-resistant properties was studied using anatase titanium dioxide($TiO_2$) and silicon oxycarbide($SiO_xC_y$) thin film. $TiO_2$ and $SiO_xC_y$ thin films were sequentially deposited on a glass substrate by DC sputtering and PECVD, respectively. The optical properties were measured by UV-Vis-NIR spectrophotometer. The abrasion-resistance and the hydrophilicity were observed by a taber abrasion tester and a contact angle analyzer, respectively. The $TiO_2/SiO_xC_y$ double-layer thin film had an average transmittance of 91.3%, which was improved by 10% in the visible light region (400 to 800 nm) than that of the $TiO_2$ single-layer thin film. The contact angle of $TiO_2/SiO_xC_y$ film was $6.9^{\circ}$ right after UV exposure. After 9 days from the exposure, the contact angle was $10.2^{\circ}$, which was $33^{\circ}$ lower than that of the $TiO_2$ single-layer film. By the abrasion test, $SiO_xC_y$ film showed a superior abrasion-resistance to the $TiO_2$ film. Consequently, the $TiO_2/SiO_xC_y$ double-layer film has achieved superior anti-reflection, hydrophilicity, and abrasion resistance over the $TiO_2$ or $SiO_xC_y$ single-layer film.

• Electrical & Electronic Materials
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• v.16 no.9
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• pp.64.2-65
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• 2003

A 4 nm layer of ZrOx (targeted x-2) was deposited on an interfacial layer(IL) of native oxide (SiO, t∼1.2 nm) surface on 200 mm Si wafers by a manufacturable atomic layer chemical vapor deposition technique at 30$0^{\circ}C$. Some as-deposited layers were subjected to a post-deposition, rapid thermal annealing at $700^{\circ}C$ for 5 min in flowing oxygen at atmospheric pressure. The experimental x-ray diffraction, x-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and high-resolution parallel electron energy loss spectroscopy results showed that a multiphase and heterogeneous structure evolved, which we call the Zr-O/IL/Si stack. The as-deposited Zr-O layer was amorphous $ZrO_2$-rich Zr silicate containing about 15% by volume of embedded $ZrO_2$ nanocrystals, which transformed to a glass nanoceramic (with over 90% by volume of predominantly tetragonal-$ZrO_2$(t-$ZrO_2$) and monoclinic-$ZrO_2$(m-$ZrO_2$) nanocrystals) upon annealing. The formation of disordered amorphous regions within some of the nanocrystals, as well as crystalline regions with defects, probably gave rise to lattice strains and deformations. The interfacial layer (IL) was partitioned into an upper Si $o_2$-rich Zr silicate and the lower $SiO_{x}$. The latter was sub-toichiometric and the average oxidation state increased from Si0.86$^{＋}$ in $SiO_{0.43}$ (as-deposited) to Si1.32$^{＋}$ in $SiO_{0.66}$ (annealed). This high oxygen deficiency in $SiO_{x}$ indicative of the low mobility of oxidizing specie in the Zr-O layer. The stacks were characterized for their dielectric properties in the Pt/{Zr-O/IL}/Si metal oxide-semiconductor capacitor(MOSCAP) configuration. The measured equivalent oxide thickness (EOT) was not consistent with the calculated EOT using a bilayer model of $ZrO_2$ and $SiO_2$, and the capacitance in accumulation (and therefore, EOT and kZr-O) was frequency dispersive, trends well documented in literature. This behavior is qualitatively explained in terms of the multi-layer nanostructure and nanochemistry that evolves.ves.ves.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.2
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• pp.101-106
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• 2009

In this paper, Thin films of $HfO_2$/Hf were deposited on p-type wafer by Atomic Layer Deposition (ALD). We studied the electrical and material characteristics of $HfO_2$/Hf/Si MOS capacitor depending on thickness of Hf metal layer. $HfO_2$ films were deposited using TEMAH and $O_3$ at $350^{\circ}C$. Samples were then annealed using furnace heating to $500^{\circ}C$. Round-type MOS capacitors have been fabricated on Si substrates with $2000\;{\AA}$-thick Pt top electrodes. The composition rate of the dielectric material was analyzed using TEM (Transmission Electron Microscopy), XRD (X-ray Diffraction) and XPS (X-ray Photoelectron Spectroscopy). Also the capacitance-voltage (C-V), conductance-voltage (G-V), and current-voltage (I-V) characteristics were measured. We calculated the density of oxide trap charges and interface trap charges in our MOS device. At the interface between $HfO_2$ and Si, both Hf-Si and Hf-Si-O bonds were observed, instead of Si-O bond. The sandwiched Hf metal layer suppressed the growing of $SiO_x$ layer so that $HfSi_xO_y$ layer was achieved. And finally, the generation of both oxide trap charge and interface trap charge in $HfO_2$ film was reduced effectively by using Hf metal layer.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.449-452
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• 1998

We have studied the oxidatio nrte of $Si_{1-x}Ge_{x}$ epitaxial layer grown by MBE(molecular beam epitaxy). Oxidation were performed at 700.deg. C, 800.deg. C, 900.deg. C, and 1000.deg. C. After the oxidation, the results of AES(auger electron spectroscopy) showed that Ge was completely rejected out of the oxide and pile up at $SiO_{2}/$Si_{1-x}Ge_{x}$ interface. It is shown that the presence of Ge at the $SiO_{2}$/$Si_{1-x}Ge_{x}$ interface changes the dry oxidation rate. The dry oxidation rate was equal to that of pure Si regardless of Ge mole fraction at 700.deg. C and 800.deg.C, while it was decreased at both 900.deg. C and 1000.deg.C as the Ge mole fraction was increased. The ry oxidation rates were reduced for heavy Ge concentration, and large oxidation time. In the parabolic growth region of $Si_{1-x}Ge_{x}$ oxidation, The parabolic rate constant are decreased due to the presence of Ge-rich layer. After the longer oxidation at the 1000.deg.C, AES showed that Ge peak distribution at the $SiO_{2}$/$Si_{1-x}Ge_{x}$ interface reduced by interdiffusion of silicon and germanium.

• ETRI Journal
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• v.31 no.6
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• pp.675-679
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• 2009

$Ti_xSi_{1-x}O_y$ (TSO) thin films are fabricated using plasma-enhanced atomic layer deposition. The Ti content in the TSO films is controlled by adjusting the sub-cycle ratio of $TiO_2$ and $SiO_2$. The refractive indices of $SiO_2$ and $TiO_2$ are 1.4 and 2.4, respectively. Hence, tailoring of the refractivity indices from 1.4 to 2.4 is feasible. The controllability of the refractive index and film thickness enables application of an antireflection coating layer to TSO films for use as a thin film solar cell. The TSO coating layer on an Si wafer dramatically reduces reflectivity compared to a bare Si wafer. In the measurement of the current-voltage characteristics, a nonlinear coefficient of 13.6 is obtained in the TSO films.

• Journal of the Korean Vacuum Society
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• v.19 no.5
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• pp.341-346
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• 2010

In this paper, anti-reflection coating was investigated for decreasing the reflection in visible range of 400~650 [nm] through four staked layers of $Si_xO_y$ and $Si_xN_y$ thin films prepared by reactive sputtering method. Si single crystal of 6 [inch] diameter was used as a sputtering target. Ar and $O_2$ gases were used as sputtering gases for reactive sputtering for the $Si_xO_y$ thin film, and Ar and $N_2$ gases were used for reactive sputtering for the $Si_xN_y$ thin film. DC pulse power of 1900 [W] was used for the reactive sputtering. Refractive index and deposition rate were 1.50 and 2.3 [nm/sec] for the $Si_xO_y$, and 1.94 and 1.8 [nm/sec] for the $Si_xN_y$ thin film, respectively. Considering the simulation of the four layer anti-reflection coating structure with the above mentioned films, the $Si_xO_y-Si_xN_y$ stacked four-layer structure was prepared. The reflection measurement result for that structure showed that a "W" shaped anti-reflection was obtained successfully with a reflection of 1.7 [%] at 550 [nm] region and a reflection of 1 [%] at 400~650 [nm] range.

• Korean Journal of Materials Research
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• v.17 no.2
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• pp.115-120
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• 2007

Polycrystalline silicon (poly-Si) thin film transistors (TFTs) might be fabricated on the mica substrate and transferred to a flexible plastic substrate because mica can be easily cleaved into a thin layer. To overcome the adhesion and stress problem between poly-Si film and mica substrate, a buffer layer consisting of $SiO_x/Ta/Ti$ three layers has been developed. The $SiO_x$ layer is for electrical isolation, the Ti layer is for adhesion of $SiO_{x}$ and mica. and Ta is for stress relief between $SiO_x$ and Ti. A TFT was fabricated on the mica substrate by a conventional Si process and was successfully transferred to a plastic substrate.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.5
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• pp.8-14
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• 2007

In this paper, $HfO_2$/Hf stacked film has been applied as the gate dielectric in MOS devices. The $HfO_2$ thin film was deposited on p-type (100) silicon wafers by atomic layer deposition (ALD) using TEMAHf and $O_3$ as precursors. Prior to the deposition of the $HfO_2$ film, a thin Hf metal layer was deposited as an intermediate layer. Round-type MOS capacitors have been fabricated on Si substrates with 2000${\AA}$-thick Al or Pt top electrode. The prepared film showed the stoichiometric components. At the $HfO_2$/Si interface, both Hf-Si and Hf-Si-O bonds were observed, instead of Si-O bond. The sandwiched Hf metal layer suppressed the growing of $SiO_x$ layer so that $HfSi_xO_y$ layer was achieved. It seems that the intermediate Hf metal layer has a benefit for the enhancement of electric characteristics of gate dielectric in $HfO_2$/Si structure.