• Korean Journal of Materials Research
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• v.12 no.6
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• pp.508-512
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• 2002

$2000{\AA}-SiO_2/Si(100)$ and $560{\AA}-Si_3N_4/Si(100)$ wafers, which are 10 cm in diameter, were directly bonded using a rapid thermal annealing method. We fixed the anneal time of 30 second and varied the anneal temperatures from 600 to $1200^{\circ}C$. The bond strength of bonded wafer pairs at given anneal temperature were evaluated by a razor blade crack opening method and a four-point bonding method, respectively. The results clearly slow that the four-point bending method is more suitable for evaluating the small bond strength of 80~430 mJ/$\m^2$ compared to the razor blade crack opening method, which shows no anneal temperature dependence in small bond strength.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.9
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• pp.417-422
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• 2002

ZnO thin films were deposited on various substrates, such as Si-(111), SiO$_2$(5000 $\AA$ by thermal CVD)/Si-(100), and SiO$_2$(2000 $\AA$ by RF sputtering)/Si-(100). The (002)-orientation, surface morphology and roughness, and electrical resistivity of deposited films were measured and compared in terms of substrate. Surface acoustic wave(SAW) filters with a multilayered configuration of IDT/ZnO/SiO$_2$/Si were also fabricated and the IDT was obtained using a lift-off method. From the frequency-response characteristics of fabricated devices, the insertion loss and side-lobe rejection were estimated. The experimental results showed that the (002)-oriented growth nature of ZnO films, which played a crucial role of determining the characteristic of SAW device, was strong1y dependent upon the SiO$_2$buffer.

• Journal of the Korean Vacuum Society
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• v.11 no.3
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• pp.135-140
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• 2002

In this paper, We deposited the BST thin-film on p-type (100)Si, (100)MgO and MgO/Si substrates respectively using RF magnetron sputtering method. After the BST thin-fil m was deposited, we performed RTA(rapid thermal anneal) at $600^{\circ}C$, oxygen atmosphere and 1 min. In the XRD measurement, we observed the (110) $Ba_{0.5}Sr_{0.5}TiO_3$ main peak in all samples and the peak intensity increased after post annealing. Then we manufactured a capacitor using Al Electrode and measured I-V, C-V. In C-V measurement result values for each substrate, dielectric constant was calculated 120 (bare Si), 305(MgO/Si), 310(MgO) respectively. A leakage current density was present less than 1 $\mu\textrm{A/cm}^2$ at applied fields below 0.3 MV/cm. In conclusion we confirmed that MgO/Si substrates give good results for BST thin-film deposition.

• Applied Microscopy
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• v.25 no.2
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• pp.73-79
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• 1995

The oxidation of silicon wafers is an essential step in the fabrication of semiconductor devices. It is known to induce degradation of electrical properties and lattice strain of Si substrate from thermal oxidation process due to charged interface and thermal expansion mismatch from thermally grown SiO, film. In this study, convergent beam electron diffraction technique is employed to directly measure the lattice strains in Si(100) and $4^{\circ}$ - off Si(100) substrates with thermally grown oxide layer at $1200^{\circ}C$ for three hours. The ratios of {773}-{973}/{773}-{953} Higher Order Laue Zone lines were used at [012] zone axis orientation. Lattice parameters of the Si substrate as a function of distance from the interface were determined from the computer simulation of diffraction patterns. Correction value for the accelerating voltage was 0.2kV for the kinematic simulation of the [012]. HOLZ patterns. The change in the lattice strain profile before and after removal of oxide films revealed the magnitudes of intrinsic strain and thermal strain components. It was shown that $4^{\circ}$ -off Si(100) had much lower intrinsic strain as surface steps provide effective sinks for the free Si atoms produced during thermal oxidation. Thermal strain in the Si substrate was in compression very close to the interface and high concentration of Si interstitials appeared to modify the thermal expansion coefficient of Si.

• Korean Journal of Materials Research
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• v.23 no.1
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• pp.47-52
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• 2013

Graphene has been synthesized on 100- and 300-nm-thick Ni/$SiO_2$/Si substrates with $CH_4$ gas (1 SCCM) diluted in mixed gases of 10% $H_2$ and 90% Ar (99 SCCM) at $900^{\circ}C$ by using inductively-coupled plasma chemical vapor deposition (ICP-CVD). The film morphology of 100-nm-thick Ni changed to islands on $SiO_2$/Si substrate after heat treatment at $900^{\circ}C$ for 2 min because of grain growth, whereas 300-nm-thick Ni still maintained a film morphology. Interestingly, suspended graphene was formed among Ni islands on 100-nm-thick Ni/$SiO_2$/Si substrate for the very short growth of 1 sec. In addition, the size of the graphene domains was much larger than that of Ni grains of 300-nm-thick Ni/$SiO_2$/Si substrate. These results suggest that graphene growth is strongly governed by the direct formation of graphene on the Ni surface due to reactive carbon radicals highly activated by ICP, rather than to well-known carbon precipitation from carbon-containing Ni. The D peak intensity of the Raman spectrum of graphene on 300-nm-thick Ni/$SiO_2$/Si was negligible, suggesting that high-quality graphene was formed. The 2D to G peak intensity ratio and the full-width at half maximum of the 2D peak were approximately 2.6 and $47cm^{-1}$, respectively. The several-layer graphene showed a low sheet resistance value of $718{\Omega}/sq$ and a high light transmittance of 87% at 550 nm.

• Korean Journal of Materials Research
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• v.11 no.2
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• pp.71-75
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• 2001

The reaction stability of nickel with side-wall materials of SiO$_2$ and Si$_3$N$_4$ on p-type 4"(100) Si substrate were investigated. Ni on 1300 $\AA$ thick SiO$_2$ and 500 $\AA$ - thick Si$_3$N$_4$ were deposited. Then the samples were annealed at 400, 500, 750 and 100$0^{\circ}C$ for 30min, and the residual Ni layer was removed by a wet process. The interface reaction stability was probed by AES depth Profiling. No reaction was observed at the Ni/SiO$_2$ and Ni/Si$_3$N$_4$, interfaces at 400 and 50$0^{\circ}C$. At 75$0^{\circ}C$, no reaction occurred at Ni/SiO$_2$ interface, while $NiO_x$ and Si$_3$N$_4$ interdiffused at Ni/Si$_3$N$_4$ interface. At 100$0^{\circ}C$, Ni layers on SiO$_2$ and Si$_3$N$_4$ oxidized into $NiO_x$ and then $NiO_x$ interacted with side-wall materials. Once $NiO_x$ was formed, it was not removed in wet etching process and easily diffused into sidewall materials, which could lead to bridge effect of gate-source/drain.

• Korean Journal of Materials Research
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• v.13 no.5
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• pp.279-284
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• 2003

The $CoSi_2$ process is widely employed in a salicide as well as an ohmic layer process. In this experiment, we investigated the characteristics of $CoSi_2$ films by combinations of I-type (TiN 100$\AA$/Co 150$\AA$), II-type(TiN 100$\AA$/Co 150$\AA$/Ti 50$\AA$), III-type(Ti 100$\AA$/Co 150$\AA$/Ti 50$\AA$), and IV-type(Ti 100$\AA$/Co 150$\AA$/Ti 100$\AA$). Sheet resistances of $CoSi_2$ show the lowest resistance with 2.9 $\Omega$/sq. in a TiN/Co condition and much higher resistances in conditions simultaneously applying Ti capping layers and Ti interlayers. Though we couldn't observe a $CoSi_2$roughness dependence on the film stacks from RMS values, Ti capping layers turned into 78∼94$\AA$ thick TiN layers of (200) preferred orientation at $N_2$ambient. In addition, Ti interlayers helped to form the epitaxial $CoSi_2$with (200) preferred orientation and ternary compounds of Co-Ti-Si. We propose that film structures of II-type and III-type may be appropriate in the salicide process and the ohmic layer process from the viewpoint of Co diffusion kinetics and the CoSi$_2$epitaxy.

• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.765-769
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• 2003

Time-Of-flight Impact-Collision Ion Scattering Spectroscopy (TOF-ICISS) using 2 keV He$\^$+/ ion was applied to study the geometrical structure of the Si(100) surface. The scattered ion intensity was measured along the [011] azimuth varying the incident angle. The focusing effects were appeared at the incident angles of 20$^{\circ}$, 28$^{\circ}$, 46$^{\circ}$, 63$^{\circ}$, and 80$^{\circ}$. The Si atomic position was simulated by calculating the shadow cone to explain the five focusing effects. The four focusing effects at 28$^{\circ}$, 46$^{\circ}$, 63$^{\circ}$, and 80$^{\circ}$ resulted from the {011} surface where no dimers existed on the outermost surface. On the contrary, the scattering between two Si atoms in a dimer resulted in the focusing peak at 20$^{\circ}$.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1428-1435
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• 2019

The total ionizing dose (TID) and non ionizing energy loss (NIEL) effects of 100 MeV phosphorous ($P^{7+}$) and 80 MeV nitrogen ($N^{6+}$) ions on 200 GHz silicon-germanium heterojunction bipolar transistors (SiGe HBTs) were examined in the total dose range from 1 to 100 Mrad(Si). The in-situ I-V characteristics like Gummel characteristics, excess base current (${\Delta}I_B$), net oxide trapped charge ($N_{OX}$), current gain ($h_{FE}$), avalanche multiplication (M-1), neutral base recombination (NBR) and output characteristics ($I_C-V_{CE}$) were analysed before and after irradiation. The significant degradation in device parameters was observed after $100MeV\;P^{7+}$ and $80MeV\;N^{6+}$ ion irradiation. The $100MeV\;P^{7+}$ ions create more damage in the SiGe HBT structure and in turn degrade the electrical characteristics of SiGe HBTs more when compared to $80MeV\;N^{6+}$. The SiGe HBTs irradiated up to 100 Mrad of total dose were annealed from $50^{\circ}C$ to $400^{\circ}C$ in different steps for 30 min duration in order to study the recovery of electrical characteristics. The recovery factors (RFs) are employed to analyse the contribution of room temperature and isochronal annealing in total recovery.

• Journal of the Korean Ceramic Society
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• v.41 no.3
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• pp.197-201
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• 2004

SiO$_2$ and SiON thick films were deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique on silicon wafer (100) using SiH$_4$ and $N_2$O as precursor gases. In this work, the influence of rf power, and rf bias power on the optical and physical properties of SiO$_2$ and SiON thick films is presented. The refractive index decreases with increasing rf power, and rf bias power. The refractive index of the films varied from 1.4493 to 1.4952 at wavelength at 1552 nm, with increasing rf power, the nitrogen content decreases while the oxygen content increases, in a manner that the O/N ratio increases approximately linearly.