J. Plasma Fusion Res. SERIES, Vol.7 (2006) 303-306

Nitrogen Ion Implantation in Pure Aluminium
GHORANNEVISS Mahmood, SARI Amir H., DORRANIAN Davoud, KHORSHID Pejman1 ,S. HAJIHOSSEINI G. Hassan, SHOKOUHY Ali and HESABI Maryam
Plasma Physics Research Center, Science and Research Campus of Islamic Azad University, Tehran, Iran1 Islamic Azad University, Mashhad Branch, Mashhad, Iran（Received: 5 October 2004 / Accepted: 10 January 2006）

Abstract
In this study nitrogen ion implantation at doses from 4 × 1017 to 1 × 1019 ions/cm2 and energy of 80 keV inpure aluminium is investigated. By means of x-ray diﬀractometry the phase composition was characterized.
Nitrogen and aluminium nitride distribution in samples at diﬀerent doses was analyzed using SIMS. Hardnessof samples before and after implantation was tested by Vickers instrument. The SEM technique has been used
for topographical studies of samples in diﬀerent conditions. The results show that the hardness of samples
after ion implantation process and because of formation of aluminium nitride phase increases dramatically,
but above the dose of 5 × 1018 ions/cm2 it decreases.
Keywords:aluminium, nitrogen ion implantation, XRD, SIMS, Hardness Vickers
of aluminium samples performed at doses of 5 × 1017 ,1 × 1018 , 5 × 1018 and 1 × 1019 ions/cm2 .
The phase composition of nitrogen-implanted samples was analyzed using x-ray diﬀraction in the Θ − 2Θmode and λ = 1.5418 Å of CuKα radiation. The presence of nitride in all implanted samples was revealedby the spectrum of Fig. 1 as AlN in (111), (200), (220),(311) and (222) planes with wurtzite structure.
The eﬀect of nitrogen implantation in microhandness
properties of samples was tested by using Vickers instrument (see Fig. 2). It can be concluded that the hardness of samples improves after nitrogen ion implantation and extend of improvement increases with dose.
The maximum hardness appears at a nitrogen ion dose

1．Introduction
It has been established that ion implantation is atechnique for producing a modification in the structure of metals by formation of new crystalline phases,
metastable or amorphous , and thus to improve the surface properties. In the past few years, implantationof nitrogen in aluminium has been widely investigated,both in the semiconductor and tribology fields becauseof the potential application of the nitride formed (passivation of semiconductor surfaces, transmission of surface acoustic waves, piezoelectric materials etc.). Tribological properties such as handness, friction, wear
and corrosion can be improved [1-10]. The importanceof aluminium nitride is because of its extreme handness,
its electrical insulating properties (a band gap approximately 6.3 eV wide) and its high melting point (about2400 ℃).
The results in the literature about the formation of
AlN after nitrogen ion implantation are few and partly
contradictory [11]. In the following study the eﬀects ofnitrogen ion implantation in pure aluminium is investigated.
2．Experiments and results
In the experiments the samples with 2 mm thickness
made of pure aluminium (99.96 % purity) were used.
The samples were implanted by using 80 keV ion implanter and unseparated nitrogen beam. The increase of
the sample temperature was ensured solely by incoming
ion beam without any additional heating. Implantation

Fig. 1 XRD analysis of a typical sample implanted atdose of 5 × 1018 ions/cm2
C 2006 by The Japan Society of Plasma

Science and Nuclear Fusion Research

Corresponding author’s e-mail: amirsari@gmail.com (SARI Amir H.)

303

Nitrogen Ion Implantation in Pure Aluminium

(a)

(b)

Fig. 2 Microhardness versus different nitrogen ion doseof 5 × 1018 ions/cm2 . Over this dose, the hardness decreases. This may caused by defects due to the excess
ion irradiation.
Nitrogen and aluminium nitride distribution in implanted samples were obtained by using secondary ion
mass spectrometry technique (SIMS) . The experiments
performed by SIMS CAMECA IMS-6 F at Plasma
Physics Research Center of Islamic Azad University.
These profiles are shown in Fig. 3 (a) to 3 (c). One
can observe that the shape of the nitrogen distribution
in Fig. 3 (a) is Gaussian for lowest dose. For higher
doses, the distributions became larger. These profiles
also confirm that by increasing the nitrogen ion dose
penetration depth of nitrogen decreases which could be
because of enhancing the formation of aluminium nitride phase (AlN) that dose not allow nitrogen ions topenetrate more. This latter result, can be confirmed bycomparison of Fig. 3 (a) to 3 (c) from the distribution ofnitrogen and aluminium nitride in aluminium for samples implanted at various ion doses.
Figure 4 show the SEM images of unimplanted andnitrogen-implanted samples at diﬀerent doses. It can beclearly seen that when the implantation dose increase,the surface morphology changes dramatically.

(c)

3．Conclusion
The results obtained in the present work can be summarized as follows. These experiments confirm the formation of the desired aluminium nitride precipitates bynitrogen ion implantation in pure aluminium. It was
found that nitrogen implantation into aluminium was
eﬀective in enhancing the hardness of the aluminium
surface, which is attributed to the formation of the crystalline AlN produced by nitrogen implantation. The
hardness increasing did not continue at nitrogen ion
dose above 5 × 1018 ions/cm2 . It could be caused by in-Fig. 3 SIMS analysis shows nitrogen and aluminium nitride distribution in samples implanted at doses of(a) 5 × 1017 , (b) 1 × 1018 and (c) 1 × 1019 ions/cm2 .

crease of defects at higher dose. SIMS analysis showedthat by increasing the ion dose the penetration depth ofnitrogen implanted ions decrease.

304

Nitrogen Ion Implantation in Pure Aluminium

(a)

(b)

(c)

(d)

(e)
Fig. 4 SEM images presenting the surface of Al samples with increasing ﬂuencies of nitrogen ions : (a) unimplanted Al, (b)Al implanted up to 4 × 1017 ion / cm2 , (c) 1 × 1018 , (d) 5 × 1018 and (e) 1 × 1019 ion / cm2 . The magniﬁcation is 3500x.

305

Nitrogen Ion Implantation in Pure Aluminium

Acknowledgements
The work was supported by Plasma Physics Research Center, Science and Research Campus of Islamic
Azad University.

[1]
[2]
[3]
[4]

[5]

H. Herman, Nucl. Instrum. Methods Phys. Res.
182/183, 887 (1981).
[6] A. Kujore, S.B. Chakrabortty , E.A. Starke andK.O. Legg, Nucl. Instrum. Methods Phys. Res.
182/183, 949 (1981).
[7] T. Vaijoranta, J. Hirvonen and A. Anttila , Thin
Solid Films 75, 241 (1981).
[8] G. Dearnaley, Mater. Sci. Eng. 69, 139 (1985).
[9] B. Doyle, D.M. Follstaedt and S.T. Picraux, Nucl.
Instrum. and Methods Phys. Res. B718 166(1985).
[10] B. Rauschenbach, Nucl. Instrum. Methods Phys.
Res. B15, 756 (1986).
[11] B. Rauschenbach, A. Kolitsch and E. Richter,Thin Solid Films, 109, 37-45 (1983).

References
G. Dearnaley and N.E.W. Hartley , This Solid
Films 54, 215 (1978).
J.K. Hirvonen, J. Vac. Sci. Technol. 15, 1662
(1978).
H.T. Li, Nucl. Instrum. Methods Phys. 182/183,915 (1981).
P.D. WE kao and J.G. Byrne, Fatigue Fract. Eng.
Mater. Struct. 3, 271 (1981).

306