Growth and Characterization of GaN thin film on Si (100) [601694]

Growth and Characterization of GaN thin film on Si (100)
substrate by Thermionic Vacuum Arc (TVA)
M Kundakçı1*, A Mantarcı2 ,E Erdoğan2

1Department of Physics, Faculty of Science, Atatürk University, Erzurum, 25250, Turkey
2Department of Physics, Faculty of Art and Science, Muș Alparslan University, Muș, 49250, Turkey

*Correspond ing author’s e -mail address: kundakci@ atauni.edu.tr
Abstract . GaN has been attractive class of material with a wide-direct band gap (3.4 eV ), one of the
significant III -Nitride materials having many advantageous device applications such as, high electron
mobility transistors, lasers, sensors, LED, detectors, and has been applicable to optoelectronic device
applications . It can be grown great number of techniques including Chemical Vapour Deposition (CVD)
Molecular Beam Epitaxy (MBE), Sputter, Pulsed Laser D eposition (PLD), and so on. In this research,
GaN thin film grown on silicon substrate by thermionic vacuum arc (TVA) technique has been
elaborately studied. Fast deposition, short production time, homogeneity, uniform nanostructure with
low roughness can be seen some merits of this method. Growth were conducted at operating pressure
1X10-6 Torr, plasma current 0.6 A and it has taken very short time being 40 seconds. For characterization
process, X -ray diffractometer (XRD) have been used to analyze structure of the film. Scanning electron
microscopy (SEM) has been worked to determine the structure and surface morphology of the material .
Keywords: GaN, Thermionic Vacuum Arc , III-Nitrides
1. Introduction

Recent years, GaN material has turned into more interesting owing to direct -wide band gap (3.4 eV),
feature of high thermal conductivity [1-5]. This material has been powerful nominee to apply to optical
device [6] with short wavelength, light emitting diode device, high -power transistor, data storag e
memory device . Many techniques can be used for deposition GaN thin film given as follow: Molecular
Beam Epitaxy (MBE) [6], Sputter, Pulsed Laser Deposition (PLD), Chemical Vapour Deposition
(CVD), and sol gel method [1-3], spin coating. These methods for growing GaN thin film has been
already presented in literature.
In this work, benefitting from Thermionic Vacuum Arc (TVA) which has been plasma deposition
technique , GaN thin film was deposited on Si (100) substrate and it has been inve stigated
characterization of the material in detail. Mechanism of TVA has not operated as reactive deposition
mechanism . We have used Thermionic Vacuum Arc (TVA) method because of some merits and these
are given as following: very short production time, high deposition rate, high quality film’s properties,
homogeneity -compact, nanostructure with low roughness. Grown film was characterized by X -ray
diffractometer (XRD), scanning electron m icroscopy (SEM) . To investigate structure of the film, XRD Page 1 of 5 AUTHOR SUBMITTED MANUSCRIPT – MRX-103036
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60

measurements were conducted. To comprehend structure and surface morphology of the material,
scanning electron microscopy (SEM) measurement was performed.

Our motivation has been two perspectives, which are meth od and material, for this research. From
material perspective, GaN material has been promising and attractive material to work with because it
has some advantages such as high electron mobility [7] (over 2000 𝑐𝑚2𝑉−1𝑠−1 at room temperature),
high melti ng point [8] ( 2500 𝐶°), high breakdown voltage [9], mechanically hard material, thermally
stable. Also, because of all these features, it has been used for high power electronic device and
optoelectronic device application. Furthermore, we have wanted to have information on material
structural and electrical properties. From method perspective , we have chosen Thermionic Vacuum Arc
(TVA) as a growth method owing to low cost and faster production and some advantages mentio ned
above .

2. Method

To grow GaN t hin film on silicon substrate, non-reactive Thermionic Vacuum Arc (TVA) method has
been used. TVA has been a generator of anodic plasma and it can grow thin film, too. Organic ions at
TVA discharge and metal have been incorporated with each other. Therefore, layer of GaN has been
caught on Silicon substrate. Simple figure of Thermionic Vacuum Arc (TVA) system has been given in
Figure 1. We have presented mechanism of original deposition which gives rise to very s hort growth
time of 40 seconds to gro w GaN thin film. We have p ut GaN bulk with high purity on crucible for anode
side. Growth condition has been significant for accurate result and our growth condition were following:
current of filament ( 18 𝐴 ) , operating pressure (10−6 𝑇𝑜𝑟𝑟 ) , growth time (40 sec.), applied
voltage 200 𝑉 , and plasma current 0.6 𝐴 . We had a film with thickness 200 −300 𝑛𝑚. Subsequently,
grown film was characterized by X -ray diffractometer (XRD), sca nning electron microscopy (SEM) .
Scanning electron microscopy (SEM) has been studied to determine the structure and surface
morphology of the material. X -ray diffractometer (XRD) have been used to analyse structure of the film.

Figure 1. Schematic view of the TVA system [10]
3. Result and discussion

Thickness of GaN film was measured by thin film analyser of filmetrics F20 . X-ray diffraction
measurement was conducted to analyse composition of film and knowledge related to crystal. Figure 2
has displayed the XRD pattern of GaN thin film. From the XRD measurement, interplanar distance , 2θ
and full width half maximum (FWHM) were calculated. These values have been given in Table 1. The
Page 2 of 5 AUTHOR SUBMITTED MANUSCRIPT – MRX-103036
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60

peak of 330 is commonly reported as the diffraction from (101̅0) planes of hexagonal GaN [11 -13]. As
shown in Figure 2, the peak of 330 has been shifted to 32.800 .The behavior of pattern has been seen
clearly, and it has b een evaluated that this little shifting (0.200) has come from impurities and defects
that was occurred at gr owing process . The XRD peak of the Si (100) substrate is also detected at
2θ=69.200.

Figure 2. XRD spectrum of deposited GaN thin films on Si substrate.

Table 1 . The structural parameters of GaN thin films deposited by TVA on Si substrate

Sample (hkl) FWHM 2θ (Observed) 2θ (Literature) d-values (Å)
GaN 101̅0 0.119 32.800 33.000 2.73
Si 100 0.065 69.200 ~70.000 1.36

By using Scanning electron microscopy (SEM), structure and surface morphology of the material
can be determined . Figure 3 has displayed Scanning electron microscopy (SEM) images of material. It
has point out that material demonstrates hexagonal structure. Deposited films are dense, smooth, well
adhered to the substrate and continue without any holes and cracks.
Some cell ’ diameters were given in this image. These images were attained at 300.000 ×
magnification. Applied high voltage has been at 30.000 𝑘𝑉 . This measurement has concluded that it
present s the formation of GaN thin film.

20 25 30 35 40 45 50 55 60 65 70 75 801001000
30.0 30.5 31.0 31.5 32.0 32.5 33.0 33.5 34.0 34.5 35.0 35.5 36.0050100150200250300350400450500550600Intensity(a.u.)
2
GaN
2Intensity(a.u.)SiPage 3 of 5 AUTHOR SUBMITTED MANUSCRIPT – MRX-103036
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60

Figure 3. Scanning Electron Microscopy (SEM) images of grown material.

Figure 4 shows the EDX spectrum of GaN film grown on Si substrate. The elemental analysis results
confirmed the presence of the Si, Ga , N, In and Oxygen in the film . The source of Indi um, the pollution
are already existing in the TVA system. Also Oxygen is always in the TVA system at 1×10-6 Torr
pressure.

Figure 4. EDX spectrum of the deposited GaN film on silicon substrate

4. Conclusion

In this research, by using thermionic vacuum arc (TVA) technique having advantageous properties such
as short production time, fast deposition, homogeneity, uniform nanostructure with low roughness, GaN
thin film has been deposited on Si (100) substrate. From the XRD measur ement the peak value
2θ=32.800 is commonly reported as the diffraction from (101̅0) planes of hexagonal GaN and 𝑑=
2.73 Å were found. These results have been compatible with literature. Scanning electron microscopy
has shown granular and dense structure of material, and some cell’s diameter value s have been
determined as 58.72,52.14,61.99,60.41 𝑛𝑚. The pollution present in the TVA system effect the
growth condition and crystal quality. These results have demonstrated that thermionic vacuum arc
(TVA) method can be used for production of GaN with high quality of film, and also with low cost.
Page 4 of 5 AUTHOR SUBMITTED MANUSCRIPT – MRX-103036
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60

References
[1] H. Qui, C. Chuanbao , H. Zhu, Synthesis of nanocrystalline GaN by the sol –gel method , Materials
Science and Engineering: B 136 (2007) 33-36.
[2] G. Sinha, K. Adhikary, S. Chaudhuri , Synthesis and optical characterization of c -axis oriented
GaN thin films on amorphous quartz glass via sol –gel process Applied Surface Science 254
(2008) 5257-5260.
[3] K. Sardar , A.Rajua and G. Subbannac , Epitaxial GaN films deposited on sapphire substrates
prepared by the sol –gel method Solid State Communications 125 (2003) 355-358.
[4] A.Majida , A. Dara, A. Nabia, A. Shakoorb, N. Hassanc, A. Junjuad, Z. Jianjune , Optical,
electronic and magnetic properties of Cr:GaN thin films Materials Chemistry and Physics 136
(2012) 809-815.
[5] D.Kanga, J. Kwon b, J. Shimc, H. Leec, M. Hana, Highly conductive GaN anti -reflection layer at
transparent conductin g oxide/Si interface for silicon thin film solar cells Solar Energy
Materials and Solar Cells 105 (2012) 317-321.
[6] E. Martinez -Guerrero , C. Adelmann , F. Chabuel , J. Simon, N. T. Pelekanos, G. Mula, B.
Daudin, G. Feuillet and H. Mariette , Self-assembled zinc blende GaN quantum dots grown by
molecular -beam epitaxy , Appl. Phys. Lett. 77 (2000) 809-811.
[7] X. Hea,D. Zhaoa, D. Jianga, J. Zhua, P.Chena, Z. Liua, L. Lea, J.Yanga , X.Lia, J.Liub, J.
Zhangb and H. Yangb, GaN high electron mobility transistors with AlInN back barriers
Journal of Alloys and Compounds 662 (2016) 16-19.
[8] W. Moon, H. Kim and C. Choi, Molecular dynamics simulation of melting behavior of GaN
nanowires Scripta Materialia 56 (2007) 345-348.
[9] W. Saito, T. Suwa , T. Uchihara, T.Naka, T. Kobayashi , Breakdown behaviour of high -voltage
GaN-HEMTs Microelectronics Reliability 55 (2015) 1682-1686.
[10] S. Pat, Ș. Korkmaz, S. Özen and V. Șenay, GaN thin film deposition on glass and PET
substrates by thermionic vacuum arc (TVA), Materials Chemistry and Physics 159 (2015) 1-5.
[11] M. Samsudin, N. Zainal and Z. Hassan , Controlled porosity of GaN using different pore
size of Si (100) substrates Superlattices and Microstructures 73 (2014) 54-59.
[12] C.G. Zhang, L.F. Bian, W.D. Chen, C.C. Hsu, Effect of growth conditions on the GaN thin film
by sputtering deposition, J.Cryst. Growth 299 (2007) 268 –271.
[13] D.M.G. Leite, A.L.J. Pereira, L.F. da Silva, J.H. Dias da Silva, Nanocrystalline GaN and
GaN:H films grown by RF -magnetron sputtering, Braz. J. Phys. 36 (3B) (2006) 978-981 Page 5 of 5 AUTHOR SUBMITTED MANUSCRIPT – MRX-103036
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60