• JSTS:Journal of Semiconductor Technology and Science
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• 제3권1호
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• pp.1-12
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• 2003

This paper describes a study on the abnormal behavior of the electrical characteristics of the (n)GaAs/Ti/Pt/Au Schottky contacts prepared by the two techniques of electron beam deposition and rf sputtering and after an annealing treatment. The samples were characterized by I-V and C-V measurements carried out over the temperature range of 150 - 350 K both in the as prepared state and after a 300 C, 30 min. anneal step. The variation of ideality factor with forward bias, the variation of ideality factor and barrier height with temperature and the difference between the capacitance barrier and current barrier show the presence of a thin interfacial oxide layer along with barrier height inhomogenieties at the metal/semiconductor interface. This barrier height inhomogeneity model also explains the lower barrier height for the sputtered samples to be due to the presence of low barrier height patches produced because of high plasma energy. After the annealing step the contacts prepared by electron beam have the highest typical current barrier height of 0.85 eV and capacitance barrier height of 0.86 eV whereas those prepared by sputtering (at the highest power studied) have the lowest typical current barrier height of 0.67 eV and capacitance barrier height of 0.78 eV.

• 한국재료학회지
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• 제28권5호
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• pp.268-272
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• 2018

An $Al_2O_3/AlN$ bilayer deposited on GaN by atomic layer deposition (ALD) is employed to prepare $Al_2O_3/AlN/GaN$ metal-insulator-semiconductor (MIS) diodes, and their interfacial properties are investigated using X-ray photoelectron spectroscopy (XPS) with sputter etch treatment and current-voltage (I-V) measurements. XPS analyses reveal that the native oxides on the GaN surface are reduced significantly during the early ALD stage, indicating that AlN deposition effectively clelans up the GaN surface. In addition, the suppression of Al-OH bonds is observed through the ALD process. This result may be related to the improved device performance because Al-OH bonds act as interface defects. Finally, temperature dependent I-V analyses show that the barrier height increases and the ideality factor decreases with an increase in temperature, which is associated with the barrier inhomogeneity. A Modified Richardson plot produces the Richardson constant of $A^{**}$ as $30.45Acm^{-2}K^{-2}$, which is similar to the theoretical value of $26.4Acm^{-2}K^{-2}$ for n-GaN. This indicates that the barrier inhomogeneity appropriately explains the forward current transport across the $Au/Al_2O_3/AlN/GaN$ interface.

• 한국재료학회지
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• 제27권7호
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• pp.364-368
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• 2017

We performed temperature dependent current-voltage (I-V) measurements to characterize the electrical properties of $Au/Al_2O_3/n-Ge$ metal-insulator-semiconductor (MIS) diodes prepared with and without $H_2O$ prepulse treatment by atomic layer deposition (ALD). By considering the thickness of the $Al_2O_3$ interlayer, the barrier height for the treated sample was found to be 0.61 eV, similar to those of Au/n-Ge Schottky diodes. The thermionic emission (TE) model with barrier inhomogeneity explained the final state of the treated sample well. Compared to the untreated sample, the treated sample was found to have improved diode characteristics for both forward and reverse bias conditions. These results were associated with the reduction of charge trapping and interface states near the $Ge/Al_2O_3$ interface.

• 한국전기전자재료학회논문지
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• 제21권8호
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• pp.738-748
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• 2008

In this study, it has been investigated on the changing behavior of electrical properties in $ZnO-Bi_2O_3-Sb_2O_3$ (Sb/Bi=2.0, 1.0 and 0.5) ceramics. The samples were prepared by conventional ceramic process, and then characterized by I-V, C-V curve plots, impedance and modulus spectroscopy (IS & MS) measurement. The electrical properties of ZBS systems were strongly dependent on Sb/Bi. In ZBS systems, the varistor characteristics were deteriorated noticeably with increasing Sb/Bi and the donor density and interface state density were increased with increasing Sb/Bi. On the other hand, we observed that the grain boundary reacted actively with the ambient oxygen according to Sb/Bi ratio. Especially the grain boundaries of Sb/Bi=0.5 systems were divided into two types, i.e. sensitive to oxygen and thus electrically active one and electrically inactive intergranular one with temperature. Besides, the increased pyrochlore and $\beta$-spinel phase with Sb/Bi ratio caused the distributional inhomogeneity in the grain boundary barrier height and the temperature instability. To the contrary, the grain boundary layer was relatively homogeneous and more stable to temperature change and kept the system highly nonlinear at high Bi-rich phase contents.