Chapter 3 Results and Discussion
3.3 Electrical properties
3.3.8 Current fitting
Using the 0.1 M solution to deposit two layers ZrO2 film on LNO substrate is employed to
analysis process of current transport. The static I-V curve is show in fig. 3.3.8-1, where the
curve is separated to fore portions. Fig. 3.3.8-2 ~ 3.3.8-5, Fig. 3.3.8-6 ~ 3.3.8-9, Fig. 3.3.8-10
~ 3.3.8-13 and Fig. 3.3.8-14 ~ 3.3.8-17 show the current fitting of curve (a), (b), (c) and (d),
31
respectively. In fig. 3.3.8-1, I-V curve, the symmetry current density at positive bias region
and negative region reveals the conduction process is dominated by the ZrO2 film so
conduction process of Schottky emission, space charge limited can be excluded. Indeed, the
current conduction process at high and low state region may be due to Frenkel Pool emission.
Chapter 4 Conclusion
First, resistance switching of Sol-Gel derived ZrO2 has been successfully demonstrated.
The X-Ray diffraction confirms that the formation material is ZrO2 film although the peak is
very weak due to the fact that the crystallization is not good. Moreover, the thickness is
related to different solutions of mole concentrations that have been measured with the cross
section of SEM. The I-V curves in various kinds of impurities-doped ZrO2 films do not have
significant difference in resistivity switching phenomenon of the film providing a simpler
process to fabricate ZrO2 film with the states of modulation that may be excluded.
Next, thickness effect on the bistable resistivity switching phenomenon has also been
investigated. I-V curve of forming process in the ZrO2 film do not greatly difference in
variation with thickness, except for the 20 nm film. The I-V curve measured after 5th
sweeping times show a closer current order in these different samples of thicknesses. These
results imply that the basic mechanism of bistable resistivity switching may be due to the
formation of the filament.
Finally, reliability including temperature effect and retention is also examined. The result
of temperature effect shows that the high current state in the ZrO2 film is not degraded at a
temperature up to 100 oC. Besides, the retention test present on ZrO2 film reveals a near 8
times difference between high and low current density states after 8 hr stress.
33
Process Voltage and Temperature Dependence
Schottky emission ~T2exp(+a V /T−qφB /kT)
Frenkel-Poole emission ~Vexp(+2a V /T −qφB /kT)
Tunnel or field emission ~V2exp(−b/V)
Space-charge limited ~V2
Ohmic ~Vexp(-c/T)
Ionic conduction ~ exp( d'/T)
T
V −
Table 1-1 Conduction Processes in Insulators
Element Radius Ti 0.64 Zr 0.87 Nb 0.69 Mo 0.68 Ni 0.78
V 0.61 Cr 0.64
Table 2-1 Radius of Element
Fig. 1.2.1-1 Equivalent circuit of capacitor-type FeRAM (a) and FET-type FeRAM [2]
Fig. 1.2.1-2 C-V characteristic of a ferroelectric device [2]
Fig. 1.2.3-1 The structure of the OBD device and its equivalent circuit [4]
Fig. 1.3.1-1 Switching cycle and current voltage behavior of a titanium dioxide film[5]
Fig. 1.3.3-1 Switching phenomenon in nickel oxide [6]
Fig. 1.3.2-1 Switching phenomenon in nickel oxide [7]
Fig. 1.4.2-1 the structure of OUM device[14]
2 Theta (degree)
Fig. 3.1.1-1 X-Ray diffraction patterns of the sample with the solution of 0.05 M/L at temperature 500 ℃
Fig. 3.1.1-2 X-Ray diffraction patterns of the sample with the solution of 0.05 M/L at temperature 700 ℃
2 Theta (degree)
Fig. 3.1.1-3 X-Ray diffraction patterns of the sample with the solution of 0.1 M/L at temperature 500 ℃
Fig. 3.1.1-4 X-Ray diffraction patterns of the sample with the solution of 0.1 M/L at temperature 700 ℃
2 Theta (degree)
Fig. 3.1.1-5 X-Ray diffraction patterns of the sample with the solution of 0.5 M/L at temperature 500 ℃
Fig. 3.1.1-6 X-Ray diffraction patterns of the sample with the solution of 0.5 M/L at temperature 700 ℃
2 th e ta (d e g r e e )
Fig. 3.1.1-7 X-Ray diffraction patterns of ZrO2 film with solution of different mole concentration
Fig. 3.1.1-7 The relation between thickness of the film and mole concentration of the solution
2 Theta (degree)
Fig. 3.1.1-9 X-Ray diffraction patterns of the sample with the solution of 0.5 M/L at temperature 500 ℃
Fig. 3.1.1-10 X-Ray diffraction patterns of the sample with the solution of 0.5 M/L at temperature 600 ℃
2 Theta (degree)
Fig. 3.1.1-11 X-Ray diffraction patterns of the sample with the solution of 0.5 M/L at temperature 700 ℃
Fig. 3.1.1-12 X-Ray diffraction patterns of the sample with the solution of 0.5 M/L at temperature 800 ℃
Fig. 3.2-1 Plane view of SEM with sample fabricated by using the solution of 0.3 mole concentration
Fig. 3.2-2 Plane view of SEM with sample fabricated by using the solution of 0.3 mole concentration and thermal treatment at temperature 500 ℃
Fig. 3.2-3 Plane view of SEM with sample fabricated by using the solution of 0.3 mole concentration and thermal treatment at temperature 600 ℃
Fig. 3.2-4 Plane view of SEM with sample fabricated by using the solution of 0.3 mole concentration and thermal treatment at temperature 700 ℃
2 T h e ta (d e g re e )
Fig. 3.2-5 X-Ray diffraction pattern related to temperature of 500 oC in the furnace
2 Theta (degree)
Fig. 3.2-6 X-Ray diffraction pattern related to temperature of 600 oC in the furnace
Fig. 3.2-7 cross section view of SEM with sample fabricated by using the solution of 0.05 mole concentration to deposit five layers of ZrO2 films
Fig. 3.2-8 cross section view of SEM with sample fabricated by using the solution of 0.1 mole concentration to deposit five layers of ZrO2 films
Fig. 3.2-9 cross section view of SEM with sample fabricated by using the solution of 0.5 mole concentration to deposit fore layers of ZrO2 films
Voltage (V)
-30 -20 -10 0 10 20 30
Current density (A/cm2 )
10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 101
1 2
3 4
Fig. 3.3.1-1 Bistable switching current density versus voltage, sweeping of 1st time
Voltage (V)
Fig. 3.3.1-2 Bistable switching current density versus voltage sweeping of 5rd time
Pulse Number
Fig. 3.3.2-1 Current density of ZrO2 film with thickness of 30 nm measured by magnitude of pulse voltage of 12 volts with pulse width of 0.5s, pulse delay 1 sec and readout voltage of -1 volt
Pulse Number
Fig. 3.3.2-2 Current density of ZrO2 film with thickness of 45 nm measured by magnitude of pulse voltage of 15 volts with pulse width of 0.5 s, pulse delay 1 sec and readout voltage of -1 volt
Fig. 3.3.3-1 forming curve of non-doped ZrO2 film of one layer deposited by solution of 0.1 mole concentration
Voltage (V)
Fig. 3.3.3-2 forming curve of V doped ZrO2 film of one layer deposited by solution of 0.1 mole concentration
Fig. 3.3.3-3 forming curve of Cr ZrO2 film of one layer deposited by solution of 0.1 mole concentration
Voltage (V)
Fig. 3.3.3-4 forming curve of Mo ZrO2 film of one layer deposited by solution of 0.1 mole concentration
Fig. 3.3.3-1 I-V curve of 5th sweeping time of non-doped ZrO2 film
Voltage (V)
Fig. 3.3.3-1 I-V curve of 5th sweeping time of Cr doped ZrO2 film
V o lt a g e (V )
Fig. 3.3.3-1 I-V curve of 5th sweeping time of Mo doped ZrO2 film
Voltage (V)
Fig. 3.3.4-1 I-V curve of the sample with thickness of 20 nm, sweeping of first time
Voltage (V)
Fig. 3.3.4-2 I-V curve of the sample with thickness of 30 nm, sweeping of first time
Voltage (V)
Fig. 3.3.4-3 I-V curve of the sample with thickness of 45 nm, sweeping of first time
Voltage (V)
Fig. 3.3.4-4 I-V curve of the sample with thickness of 82 nm, sweeping of first time
Voltage (V)
Fig. 3.3.4-5 I-V curve of the sample with thickness of 20 nm, sweeping of 5th time
Voltage (V)
Fig. 3.3.4-6 I-V curve of the sample with thickness of 30 nm, sweeping of 5th time
Voltage (V)
Fig. 3.3.4-7 I-V curve of the sample with thickness of 45 nm, sweeping of 5th time
Voltage (V)
Fig. 3.3.4-8 I-V curve of the sample with thickness of 82 nm, sweeping of 5th time
Thickness (nm)
10 20 30 40 50 60 70 80 90
High State Current Density (A/cm2 )
10-2 10-1 100
Fig. 3.3.4-9 the order of the current density versus thickness of the ZrO2 film, sweeping of 1 time
Thickness (nm)
10 20 30 40 50 60 70 80 90
High State Current Density (A/cm2 )
10-2 10-1 100
Fig. 3.3.4-10 the order of the current density versus thickness of the ZrO2 film, sweeping of 5 times
Fig. 3.3.5-1 I-V curve of ZrO2 film deposited by solution of 0.5 mole concentration and thermal treatment in the furnace at temperature 600 oC for 30 min, 1st sweeping time
Voltage (V)
-40 -30 -20 -10 0 10 20 30 40
Current density (A/cm2 )
10-6 10-5 10-4 10-3 10-2 10-1 100 101
2 1
3 4
Fig. 3.3.5-2 I-V curve of ZrO2 film deposited by solution of 0.5 mole concentration and thermal treatment in the furnace at temperature 600 oC for 30 min, 5th sweeping time
2 Theta (degree)
Fig. 3.3.5-3 X-Ray diffraction pattern of the ZrO2 film deposited by solution of 0.5 mole concentration and thermal treatment in the furnace at temperature 600 oC for 30 min
T im e (s e c )
Fig. 3.3.6-1 Retention for this sample, the magnitude of the pulse voltage is 30 volts and the pulse width is 0.5 s
Time (sec)
0 5000 10000 15000 20000 25000 30000 35000
Ratio
Fig. 3.3.6-2 High-low leakage ration variation during retention test for this sample, the magnitude of the pulse voltage is 30 volts and the pulse width is 0.5 s
Temperature (oC)
80 100 120 140 160 180 200
Normalization High state current (a. u.)
0.0
Fig. 3.3.7 High state current after thermal treatment divide by high state current before thermal treatment versus temperature
Voltage (V)
Fig. 3.3.8-2 Schottky emission process fitting of curve (a)
V1/2
Fig. 3.3.8-3 Frenkel poole process current fitting of curve (a)
1/ V
Fig. 3.3.8-4 Field emission process fitting of curve (a)
V (volt)
Fig. 3.3.8-5 Space-charge-limited process fitting of curve (a)
V (volt)
Fig. 3.3.8-6 Ohmic fitting of curve (a)
V1/2
Fig. 3.3.8-7 Schottky emission process fitting of curve (b)
V1/2
Fig. 3.3.8-8 Frenkel poole process current fitting of curve (b)
1/ V
Fig. 3.3.8-9 Field emission process fitting of curve (b)
V (volt)
Fig. 3.3.8-10 Space-charge-limited process fitting of curve (b)
V (volt)
Fig. 3.3.8-11 Ohmic fitting of curve (b)
V1/2
Fig. 3.3.8-12 Schottky emission process fitting of curve (c)
V1 /2
0 1 2 3
ln(J/V)
-3 .0 -2 .8 -2 .6 -2 .4 -2 .2 -2 .0
Fig. 3.3.8-13 Frenkel poole process current fitting of curve (c)
1/ V
0 2 4 6 8 10 12
ln(J/V
2)
-2.5 -2.0 -1.5 -1.0 -0.5 0.0
Fig. 3.3.8-14 Field emission process fitting of curve (c)
V (volt)
Fig. 3.3.8-15 Space-charge-limited process fitting of curve (c)
V (volt)
Fig. 3.3.8-16 Ohmic fitting of curve (c)
V1/2
Fig. 3.3.8-17 Schottky emission process fitting of curve (d)
V1/2
Fig. 3.3.8-18 Frenkel poole process current fitting of curve (d)
1/ V
Fig. 3.3.8-19 Field emission process fitting of curve (d)
V (volt)
Fig. 3.3.8-20 Space-charge-limited process fitting of curve (d)
V (volt)
0 2 4 6 8 10 12 14 16
J (mA/cm
2)
0.0 0.1 0.2 0.3 0.4
Fig. 3.3.8-21 Ohmic fitting of curve (d)
Chapter 1
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[6] S. Basavaiah, and K. O. park, “Bistable switching and conduction mechanisms in Nb-Nb2O5-Bi junctions, “ IEEE Trans. Electron Devices, ED-20, pp. 149-157, Feb. 1973.
[7] W. R. Hiatt, T. W. Hickmott, “Bistable Switching in Niobium Oxide Diodes”, Appl. Phys.
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[8] J. C. Bruyere and B. K. Chakraverty, “Switching And Negative Resistance In Thin Films of Nickel Oxide”, Appl. Phys. Lett., 16, pp. 40-43, Jan. 1970.
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自 傳
學生：林昭正
性別：男
生日：民國 68 年 11 月 03 日
出生地：台灣省
學歷：
國立台北科技大學電機工程學系 (90 年 9 月~92 年 6 月)
國立交通大學電子研究所碩士班 (92 年 9 月~94 年 6 月)