• Electrical & Electronic Materials
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• v.1 no.3
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• pp.251-260
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• 1988

n형 GaAs에 음성접촉을 형성함에 있어서 Au-Ge 공융합금을 용해시키는 alloying 보다는 sintering을 필요로 하는 Su-Pd-Ge계의 새로운 융성접촉을 도입하였다. Au-Pd-Ge계의 최적의 음성조건을 조사하기 위하여 Au/Pd/Ge, Au/Ge/Pd, Au/Pd/Ge/Pd 그리고 Au/Pd/Au/Ge 음성접촉을 제조하였다. 비접촉저항을 조사하는데 있어서 sintering 온도는 390-450.deg.C사이였고 시간은 30초에서 6분 사이였다. Au-Pd-Ge계의 비접촉저항은 alloying된 Au/Pd/Ge 접촉의 그것에 필적할 만큼 낮았으며 특히 Au/Ge/Pd 접촉은 430.deg.C, 3분의 sintering 조건에서 가장 낮은 1.2*$10^{-6}$.OMEGA..$cm^{2}$의 비접촉저항을 나타냈다. Au/Ge/Pd 접촉의 표면형상 및 접촉패턴 가장자리는 450.deg.C에서 2분 이상 sintering된 접촉을 제외하고는 sintering 후에 as-deposited 상태와 다를 바가 없었다. 430.deg.C, 3분 sintering에서 가장 낮은 비접촉저항을 나타낸 Au/Ge/Pd 접촉의 비접촉저항은 430.deg.C에서 Ge/Pd 두께 변화에 비교적 변화가 적었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.6
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• pp.491-495
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• 2007

This paper has demonstrated the electrical properties of SiGe pMOSFETs fabricated on both bulk-Si and PD SOI substrates. Two principal merits, the mobility increase in strained-SiGe channel and the parasitic capacitance reduction of SOI isolation, resulted in improvements in device performance. It was observed that the SiGe PD SOI could alleviate the floating body effect, and consequently DIBL was as low as 10 mV/V. The cut-off frequency of device fabricated on PD SOI substrate was roughly doubled in comparison with SiGe bulk: from 6.7 GHz to 11.3 GHz. These experimental result suggests that the SiGe PD SOI pMOSFET is a promising option to drive CMOS to enhance performance with its increased operation frequency for high speed and low noise applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.21-22
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• 2005

Partially-depleted Silicon on insulator metal-oxide-semiconductor field- effect transistors (PD-SOI MOSFETs) with Silicon-germanium (SiGe) layer is investigated. This structure uses SiGe layer to reduce the kink effect in the floating body region near the bottom channel/buried oxide interface. Among many design parameters influencing the performance of the device, Ge composition is presented most predominant effects, simulation results show that kink effect is reduced with increase the Ge composition. Because the bandgap of SiGe layer is reduced at higher Ge composition, the hole current between body and SiGe layer is enhanced.

• Korean Journal of Materials Research
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• v.13 no.7
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• pp.465-472
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• 2003

Pd/Ge/Ti/Pt and Pd/Ge/Pd/Ti/Au ohmic contacts to n-type InGaAs were investigated for applications to AlGaAs/GaAs HBT emitter ohmic contacts. In the Pd/Ge/Ti/Pt ohmic contact minimum specific contact resistivity of $3.7${\times}$10^{-6}$ $\Omega$$\textrm{cm}^2$ was achieved by rapid thermal annealing at $^400{\circ}C$/10 sec. In the Pd/Ge/Ti/Au ohmic contact, minimum specific contact resistivity of $1.1${\times}$10^{-6}$ $\Omega$$\textrm{cm}^2$ was achieved by annealing at 40$0^{\circ}C$/10 sec but the ohmic performance was degraded with increasing annealing temperature due to the reaction between the ohmic contact materials and the InGaAs substrate. However, non-spiking planar interface and relatively good ohmic contact (high-$10^{-6}$ /$\Omega$$\textrm{cm}^2$) were maintained after annealing at $450^{\circ}C$/10 sec. Therefore, these thermally stable ohmic contact systems are promising candidates for compound semiconductor devices. RF performance of the AlGaAs/GaAs HBT was also examined by employing the Pd/Ge/Ti/Pt and Pd/Ge/Pd/Ti/Au systems as emitter ohmic contacts. Cutoff frequencies were 63.5 ㎓ and 65.0 ㎓, respectively, and maximum oscillation frequencies were 50.5 ㎓ and 51.3 ㎓, respectively, indicating very successful high frequency operations.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.11a
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• pp.152-152
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• 1998

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.219-224
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• 2001

Pd/Ge/Ti/Pt ohmic contact to n-type InCaAs was investigated. Minimum specific contact resistivity of $3.7\times10^{-6}\; \Omega\textrm{cm}^2$ was achieved by rapid thermal annealing at $400^{\circ}C$ for 10 seconds. This was related to the formation of Pd-Ge compounds and the in-diffusion of Ge atoms to InGaAs surface. However, the specific contact resistivity increased slightly to $low-10^5\; \Omega\textrm{cm}^2$ in the case of longer annealing time. Superior ohmic contact and non-spiking planar interface between ohmic materials and InGaAs were maintained after annealing at high temperature. Therefore, this thermally stable ohmic contact system is a promising candidate for compound semiconductor devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.4
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• pp.271-275
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• 2011

In this paper, thermal stability of palladium germanide (Pd germanide) is analyzed for high performance Schottky barrier germanium metal oxide semiconductor field effect transistors (SB Ge-MOSFETs). Pd germanide Schottky barrier diodes were fabricated on n-type Ge-on-Si substrates and the formed Pd germanide shows thermal immunity up to $450^{\circ}C$. The barrier height of Pd germanide is also characterized using two methods. It is shown that Pd germanide contact has electron Schottky barrier height of 0.569~0.631 eV and work function of 4.699~4.761 eV, respectively. Pd germanide is promising for the nanoscale Schottky barrier Ge channel MOSFETs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.533-533
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• 2007

The stress effect of SiGe p-type metal oxide semiconductors field effect transistors(MOSFETs) has been investigated to compare device properties using Si bulk and partially depleted silicon on insulator(PD SOI). The electrical properties in SiGe PD SOI presented enhancements in subthreshold slope and drain induced barrier lowering in comparison to SiGe bulk. The reliability of gate oxides on bulk Si and PD SOI has been evaluated using constant voltage stressing to investigate their breakdown (~ 8.5 V) characteristics. Gate leakage was monitored as a function of voltage stressing time to understand the breakdown phenomena for both structures. Stress induced leakage currents are obtained from I-V measurements at specified stress intervals. The 1/f noise was observed to follow the typical $1/f^{\gamma}$ (${\gamma}\;=\;1$) in SiGe bulk devices, but the abnormal behavior ${\gamma}\;=\;2$ in SiGe PD SOI. The difference of noise frequency exponent is mainly attributed to traps at silicon oxide interfaces. We will discuss stress induced instability in conjunction with the 1/f noise characteristics in detail.

• Journal of the Korean Vacuum Society
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• v.11 no.1
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• pp.43-49
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• 2002

Pd/Ge/Pd/Ti/Au ohmic contact to n-type InGaAs was investigated with rapid thermal annealing conditions. Minimum specific contact resistivity of $1.1\times10^{-6}\Omega\textrm{cm}^2$ was achieved after annealing at $400^{\circ}C$/10sec, and a ohmic performance was degraded at higher annealing temperature due to the chemical reaction between the ohmic contact materials and the InGaAs substrate. However, non-spiking planar interface and relatively good ohmic contact($high-10^{-6};{\Omega}\textrm{cm}^2$) were maintained. This ohmic contact system is expected to be a promising candidate for compound semiconductor devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.151-154
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• 1998

We have investigated a correlation of the electrical properties of the Pd/Ge/Pd/Ti/Au ohmic contact on n-InGaAs with its microstructures for the high temperature application of compound semiconductor devices. The samples were heat-treated by the rapid thermal annealing at various temperatures. In the contact system, moderately good specific contact resistance was obtained even before annealing because of the low metals-InGaAs barrier height, and better ohmic performances were observed by annealing up to 400˚C. But the ohmic performance was degraded after annealing at 450˚C due to the increment of Pd$_2$Ga$\sub$5/ phases.