Microsoft Word The full thesis [v20] Cover & Abstract

2
-Pt lateral MIM 
structure with gap approximately 41 nm (b) the plot based on Fowler-Nordheim tunneling model 
-40
-20
0
20
40
0.0
5.0x10
-9
1.0x10
-8
1.5x10
-8
First
Second
Third
Current (A)
Voltage (V)
0.00
0.04
0.08
0.12
0.16
0.20
-30
-28
-26
ln(I/V
2
) (A/V
2
)
1/V (V
-1
)
First
Second
Third

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3.3 Electric characteristics of MIC diode 
Figure 3.12: The schematic illustration of the MIC diode 
To solve the problem of the lateral MIM structure, the MIC (Metal-Insulator-Carbon 
nanotube) structure is suggested. Figure 3.12 shows the schematic illustration of the MIC 
structure. The vertically aligned multi-walled carbon nanotube (MWCNT) was formed to 
selected position on Oxide/Metal layer. To remove the current flow between the bottom and 
the top electrode directly and to from electrode on top of the MWCNT, 2 um polymer (SU-8) 
was coated on CNT/Oxide/Metal structure. The thick polymer prevents the current flow. The 
almost current flows through metal-insulator-CNT-metal pathway. For positive bias, the 
small sharp nano-electrode, CNT, has a high electric field density. 
 

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Figure 3.13: the The various simulation results based on the electric potential of the MIC structure by 
COMSOL 
Figure 3.13 is the results of field simulation using COMSOL. The field distribution in 
MIC structure can be indirectly observed through various kinds of simulation results. The 
color presents the level of electric potential. All simulations were carried out under applied 5 
V and 0 V bias to the top of a CNT and the bottom of niobium, respectively. The high aspect 
ratio CNT structure can induce the field emission tunneling effect. The lower potential from 
the high ß value make the higher current flow.
Figure 3.14 shows the image after forming catalyst on the niobium electrode with thin 
SiO
2
layer for the MIC diode. Figure 3.15 shows image of the whole MIC structure and SEM 
image of a vertical aligned multi-walled carbon nanotube (MWCNT). The advantages of 
MIC structure are that it is not only easy to acquire small junction area and control of the gap 
between metallic layers, but also good field emission effect due to high aspect ratio of a CNT 
(ß ≈ 200~2000) as well as good conductivity. 

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