The effects of temperature on electrical transport properties of Al/Si Schottky diode Rajender Kumar and Subhash Chand Citation: AIP Conference Proceedings 1536, 487 (2013); doi: 10.1063/1.4810313 View online: http://dx.doi.org/10.1063/1.4810313 View Table of Contents: http://scitation.aip.org/content/aip/proceeding/aipcp/1536?ver=pdfcov Published by the AIP Publishing
This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 115.254.0.66 On: Tue, 17 Dec 2013 04:44:07
The Effects Of Temperature On Electrical Transport Properties Of Al/Si Schottky Diode. Rajender Kumar and Subhash Chand Department of Physics, National Institute of Technology, Hamirpur-177005 (H.P), India. E mail:
[email protected] and
[email protected] Abstract. The current voltage (I-V) and capacitance voltage (C-V) characteristics of Al/n-Si (111) Schottky diode are measured over wide temperature. The measured I-V data is fitted into thermionic emission diffusion (TED) equation. The temperature dependence of the barrier height and ideality factor are analyzed to understand the current transport mechanism in the Schottky diodes. The temperature dependence of barrier height is also measured from C-V characteristics. Keywords: Current-voltage characteristics, capacitance-voltage characteristics, Schottky diode, Barrier height, Ideality factor. PACS: 85.30.Hi, 73.30. +y, 61.72.j_
where, Vbi is built in potential, s is dielectric constant of semiconductor,NA is carrier concentration.
INTRODUCTION Schottky barrier diodes are very useful in solar cell and photovoltaic devices [1-3]. For efficient use of these diodes it is essential to understand the I-V characteristics of the Schottky diodes. The I-V characteristics measured over wide temperature sheds light on the nature of these Schottky diodes and helps in understanding the exact current transport mechanism in these devices [4-5] We have fabricated the schottky diodes and measured their I-V and C-V characteristics over wide temperature range.
RESULTS AND DISCUSSION These current-voltage characteristics of Schottky diode measured at various temperatures are shown in figure 1.
10-2 10-3 -5
10
The of Al/n-Si(111) diodes were fabricated by vacuum evaporation of Aluminum on silicon and annealing at 500°C for about 45 min in vacuum. The current I (V, b is expressed in term of TED equations as [1] I (V , I )
ª qI º ª q(V IR s ) ½ º Ad A T exp « b » «exp® ¾ 1» ...(1) ¬ kT ¼ ¬ ¯ KkT ¿ ¼ 2
where, Ad is diode area, A** the Richardson constant, q b S the series resistance. The measured current-voltage data of the Schottky diode is fitted in to the TED current equation (1) to estimate barrier parameters of the diodes. The temperature dependence of extracted barrier parameters e.g., barrier height and ideality factor are studied in view of TED mechanism. 1/C2 = 2{Vbi+V-(KT/q)/q s oAd2NA}
Current (A)
EXPERIMENTAL
**
Temperature 1 300 K 2 280 K 3 260 K 4 220 K 5 180 K 6 140 K 7 100 K 8 80 K 9 60 K 10 40 K 11 20 K
1
10-4
11
10-6 10-7 10-8 10-9
10-10 10-11 10-12 0.0
0.2
0.4
0.6
0.8
1.0
Forward Bias (V)
1.2
1.4
FIGURE 1. The ln(I)-V plots of Al/p-Si Schottky diodes.
The plots shows that current decreases with decrease in temperatures in consistent with equation (1).
....... (2)
Proceeding of International Conference on Recent Trends in Applied Physics and Material Science AIP Conf. Proc. 1536, 487-488 (2013); doi: 10.1063/1.4810313 © 2013 AIP Publishing LLC 978-0-7354-1160-9/$30.00
487 to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: This article is copyrighted as indicated in the article. Reuse of AIP content is subject 115.254.0.66 On: Tue, 17 Dec 2013 04:44:07
4.0x1020
3.0x1020 2.5x1020 20
2.0x10
1.5x1020 1.0x1020
300 K 280 K 260 K 220 K 180 K 140 K 100 K 80 K 60 K 40 K
20 10
Ideality factor
1 2 3 4 5 6 7 8 9 10
3.5x1020
1/C2 (Farad-2)
25
Temperature
10
1
5
5.0x1019 0
1
2
3
4
Reverse Bias (V)
5
6
FIGURE 2. The 1/C2 vs V plot of Al/p-Si Schottky diode for various temperatures at frequency 3MHz.
The Schottky barrier height was measured from both IV data and C-V data at various temperatures and is shown in figure 3. 1.0
15
0
50
100
150
200
Temperature (K)
250
300
FIGURE 4. The ideality factor derived from the I-V data at various temperatures.
Fig. 4 shows that the ideality factor measured from I-V increases with decrease in temperature.
CONCLUSION
I-V measurement C-V measurement
0.8
0.2
REFERENCES
Barrier height (V)
0.4
The Al/n-Si(111) diodes are fabricated by deposition of aluminum on n-silicon. The temperature dependence of I-V and the reverse bias C-V characteristics of Al/n-Si(111) were measured. There is discrepancy between barrier heights obtained from I-V and C-V measurements.
0.6
0.0
0
50
100
150
200
250
300
Temperature (K) FIGURE 3. The barrier height derived from I-V and C-V data at various temperatures.
Fig.3 shows that the barrier height measured from I-V is decreases linearly with decrease in temperature while the barrier height measured from C-V remain within the value 0.5V to 0.7V
1. S.M. Sze SM 2002, Physics of Semiconductor Devices 2nd Edn (New York: Wiley). 2. S.Lin,B.P.Zhang, S.W. Zeng, X.M. Cai, J.Y.Zhang,S.X. Wu,A.K. Ling,G.E. Weng,Solid State Electronics63, 105(2011). 3. M.Soylua and F.Yakuphanoglu, Thin Solid Films 519, 1950(2011). 4. S. Chand and J.Kumar,Semicond. Sci. Technol. 10, 1680 (1995). 5. M.E.Audin, O. Gullu and N. Yildirim, Physica B. 403, 131(2008)
488 to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: This article is copyrighted as indicated in the article. Reuse of AIP content is subject 115.254.0.66 On: Tue, 17 Dec 2013 04:44:07
