• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.12
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• pp.809-814
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• 2014

Spinel thin films were prepared by the spin spray technique to develop new thermal imaging materials annealed at low temperature for uncooled microbolometer applications. The spinel thin films were deposited from $[(Ni_{0.30}Co_{0.33}Mn_{0.37})_{1-x}Cu_x]_3O_4$ ($0.1{\leq}x{\leq}0.2$) solutions and then annealed at $400^{\circ}C$ for 1 h in argon. Effects of Cu content (x) and deposition time on the electrical properties of the annealed films were investigated. With increasing deposition time, the resistivity of the annealed films increased. For the annealed films deposited for 1 min, the resistivity of x=0.15 films was lower than that of x=0.1 films due to the different grain sizes. The high temperature coefficient of resistance (TCR) of the annealed films could be obtained at temperature below $50^{\circ}C$. Typically, the resistivity of $127{\Omega}{\cdot}cm$ and TCR of -5.69%/K at $30^{\circ}C$ were obtained for x=0.1 films with deposition time of 1 min annealed at $400^{\circ}C$ for 1 h in argon.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.573-576
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• 2000

The physical, electrical and piezoresitive characteristics of CrN(chromium nitride) thin-films on silicon substrates have been investigated for use as strain gauges. The thin-film depositions have been carried out by DC reactive magnetron sputtering in an argon-nitrogen atmosphere(Ar-(5∼25 %)Na$_2$). The deposited CrN thin-films with thickness of 3577${\AA}$ and annealing conditions(300$^{\circ}C$, 48 hr) in Ar-10 % N$_2$deposition atmosphere have been selected as the ideal piezoresistive material for the strain gauges. Under optimum conditions, the CrN thin-films for the strain gauges is obtained a high electrical resistivity, $\rho$=1147.65 ${\mu}$$\Omega$cm, a low temperature coefficient of resistance, TCR=-186 ppm/$^{\circ}C$ and a high temporal stability with a good longitudinal gauge factor, GF=11.17.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.181-184
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• 2002

This paper describes fabrication and characteristics of ceramic pressure sensor for working at high temperature. The proposed pressure sensor consists of a Ta-N thin-film, patterned on a Wheatstone bridge configuration, sputter deposited onto thermally oxidized Si membranes with an aluminium interconnection layer. The fabricated pressure sensor presents a low temperature coefficient of resistance, high sensitivity, low non-linearity and excellent temperature stability The sensitivity is 1.097∼1.21 mV/V$.$kgf/$\textrm{cm}^2$ in the temperature range of 25∼200$^{\circ}C$ and the maximum non-linearity is 0.43 %FS.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.5
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• pp.405-409
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• 2001

This paper describes fabrication and characteristics of metal thin-film pressure sensor for working at high temperature. The proposed pressure consists of a chrom thin-film, patterned on a Wheat stone bridge configuration, sputter-deposited onto thermally oxidized Si membranes with an aluminium interconnection layer. The fabricated pressure sensor presents a low temperature coefficient of resistance, high-sensitivity, low non-linearity and excellent temperature stability. The sensitivity is 1.097∼1.21mV/V$.$kgf/$\textrm{cm}^2$ in the temperature range of 25∼200$^{\circ}C$ and the maximum non-linearity is 0.43%FS.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.1
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• pp.17-22
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• 2017

Effects of pH value and deposition time on the electrical properties of (NMC) Ni-Mn-Cu-O and (NMCC) Ni-Mn-Cu-Co-O thin films were investigated. The NMC and NMCC films were prepared by spin spray method. The crystal structure and thickness of the annealed films were changed by the pH value and deposition time, respectively. A single phase of cubic spinel structure was confirmed for the annealed films deposited from solutions with pH 7.6. The resistivity of the annealed films was affected by the crystal structure and microstructure. The TCR (temperature coefficient of resistance) was dependent on the $Mn^{3+}/Mn^{4+}$. Typically, the resistivity of $70.5{\Omega}{\cdot}cm$ and TCR of -3.56%/K at room temperature were obtained for NMCC films deposited from solutions with pH 7.6 for 5 min, and annealed at $450^{\circ}C$ for 3 h.

• Journal of Sensor Science and Technology
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• v.18 no.2
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• pp.147-153
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• 2009

A thermal flow sensor has been fabricated and characterized, consisting of a center resistive heater surrounded by two upstream and one downstream temperature sensing resistors. The heater and temperature sensing resistors are fabricated from nitrogen-doped(n-type) polycrystalline silicon carbide(poly-SiC) deposited by LPCVD(low pressure chemical vapor deposition) on LPCVD silicon nitride films on a Si substrate. Cavities were etched into the Si substrate from the front side to create suspended silicon nitride membranes carrying the poly-SiC elements. One upstream sensor is located $50{\mu}m$ from the heater and has a sensitivity of $0.73{\Omega}$/sccm with ${\sim}15\;ms$ rise time in a dynamic range of 1000 sccm. N-type poly-SiC has a linear negative temperature coefficient and a TCR(temperature coefficient of resistance) of $-1.24{\times}10^{-3}/^{\circ}C$ from room temperature to $100^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1596-1598
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• 2002

This paper presents the characteristics of Ta-N thin-film strain gauges as high-temperature strain gauges, which were deposited on Si substrate by DC reactive magnetron sputtering in an argon-nitrogen atmosphere(Ar-($4{\sim}16%$)$N_2$). These films were annealed for 1 hour in $2{\times}10^{-6}$ Torr vacuum furnace range $500{\sim}1000^{\circ}C$. The optimized conditions of Ta-N thin-film strain gauges were annealing condition($900^{\circ}C$, 1 hr.) in 8% $N_2$ gas flow ratio deposition atmosphere. Under optimum conditions, the Ta-N thin-films for strain gauges is obtained a high resistivity, ${\rho}$=768.93 ${\mu}{\Omega}cm$, a low temperature coefficient of resistance, TCR = -84 ppm/$^{\circ}C$ and a high temporal stability with a good longitudinal gauge factor, GF = 4.12.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.8
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• pp.651-654
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• 2010

This paper describes the thermal and mechanical properties of doped thin film 3C-SiC and porous 3C-SiC. In this work, the in-situ doped thin film 3C-SiC was deposited by using atmospheric pressure chemical vapor deposition (APCVD) method at $120^{\circ}C$ using single-precursor hexamethyildisilane: $Si_2(CH_3)_6$ (HMDS) as Si and C precursors. 0~40 sccm $N_2$ gas was used as doping source. After growing of doped thin film 3C-SiC, porous structure was achieved by anodization process with 380 nm UV-LED. Anodization time and current density were fixed at 60 sec and 7.1 mA/$cm^2$, respectively. The thermal and mechanical properties of the $N_2$ doped porous 3C-SiC was measured by temperature coefficient of resistance (TCR) and nano-indentation, respectively. In the case of 0 sccm, the variations of TCR of thin film and porous 3C-SiC are similar, but TCR conversely changed with increase of $N_2$ flow rate. Maximum young's modulus and hardness of porous 3C-SiC films were measured to be 276 GPa and 32 Gpa at 0 sccm $N_2$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.391-392
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• 2008

A surface micromachined uncooled microbolometer based on the amorphous silicon was designed and fabricated. We designed the microbolometer with a pixel size of $35\times35$, $44\times44{\mu}m^2$ and a fill factor of about 70 % by considering such important factors as the thermal conductance, thermal time constant, the temperature coefficient of resistance, and device resistance. Finally, we successfully fabricated the microbolometer by using surface MEMS technology, and the properties of bolometer have been measured as such that TCR and absorptance can be achieved above -2.5%/K and about 90% with titanium layer, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.2
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• pp.169-173
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• 2005

Ni oxide thin films were formed through annealing treatment in the atmosphere after Ni thin films deposited by a r.f. magnetron sputtering method and then electric and material properties were analyzed for application to thermal sensors. Resistivity of Ni thin films decreased after annealing treatment at 30$0^{\circ}C$ and 40$0^{\circ}C$ for five hours due to crystallization of Ni thin films but the value increased over 45$0^{\circ}C$ because of Ni thin film's oxidation. Resistivity values of Ni thin films were in the range of 10.5 $\mu$Ωcm/$^{\circ}C$ to 2.84${\times}$10$^4$$\mu$Ωcm/$^{\circ}C$ according to the degree of Ni oxidation. Also temperature coefficient of resistance(TCR) values of Ni oxide thin films depended on the degree of Ni oxidation such as 2,188 ppm/$^{\circ}C$ to 5,630 ppm/$^{\circ}C$ in the temperature range of 0 $^{\circ}C$∼150 $^{\circ}C$. The results demonstrate that Ni oxide thin films of annealing treatment at 40$0^{\circ}C$ for 5hours could be more advantageous than pure Ni thin films and Pt thin films from a point of output properties and TCR, applied to thermal sensors.