Sains Malaysiana
40(1)(2011): 78–82
ICP-RIE
Dry Etching Using Cl2-based on GaN
(Punaran Kering ICP-RIE Berasaskan-Cl2 pada GaN)
Siti
Azlina Rosli*, Azlan Abdul Aziz
& Md Roslan Hashim
Nano Optoelectronics Research and Technology Laboratory
School of Physics, Universiti Sains Malaysia
11800 Minden, Pulau Pinang, Malaysia
Diserahkan: 7 Disember 2009 / Diterima: 22 Julai 2010
ABSTRACT
In this study, the plasma
characteristics and GaN etch properties of inductively coupled Cl2/Ar
and Cl2/H2 plasmas were
investigated. Our results showed that inductively coupled plasma (ICP)
etching of gallium nitride by using Cl2/Ar
and Cl2/H2 were possible to meet
the requirements (anisotropy, high etch rate and high selectivity). We have
investigated the etching rate dependency on the percentage of argon and
hydrogen in the gas mixture and the DC voltage. Surface morphology
of the etched samples was checked by SEM and AFM.
It was found that the etched surface was anisotropic and the smoothness of the
etched surface is comparable to that of polished wafer. As results, gas mixture
using Cl2/Ar, we obtained highest etching rates; 5000 Å/min
and ~0.5 nm rms roughness for n-GaN and for p-GaN, the etching rates was 3300
Å/min and ~0.7 nm for rms roughness. Meanwhile, for gas mixture using Cl2/H2,
the etching was 1580 Å/min for n-GaN and 950 Å/min for p-GaN.
Keywords: Argon; gallium
nitride; hydrogen; inductively coupled plasma etching
ABSTRAK
Dalam kajian ini,
pencirian plasma dan kandungan punaran GaN pada gandingan teraruh plasma Cl2/Ar
dan Cl2/H2 telah dikaji. Kajian
menunjukkan punaran plasma yang digandingkan secara teraruh (ICP)
pada GaN menggunakan Cl2/Ar dan Cl2/H2 akan menunjukkan keadaan yang anisotropik dengan kadar
punaran dan peratusan kepilihan yang tinggi. Kadar punaran juga bergantung
kepada peratusan argon dan hidrogen dalam campuran gas dan voltan DC.
Morfologi permukaan pada sampel yang dipunar ditentukan menggunakan SEM dan AFM.
Hasil menunjukkan bahawa permukaan GaN yang dipunar adalah anisotropik dan
licin. Bagi campuran gas Cl2/Ar, permukaan n-GaN
memberikan kadar punaran tertinggi iaitu 5000 Å/min dan purata kekasaran ~0.5
nm. Manakala bagi permukaan p-GaN, kadar punaran tertinggi adalah 3300 Å/min
dengan purata kekasaran ~0.7 nm. Bagi campuran gas Cl2/H2 pula, kadar punaran tertinggi adalah 1580 Å/min bagi
permukaan n-GaN dan 950 Å/min bagi permukaan p-GaN.
Kata kunci: Argon;
galium nitrida; hidrogen; punaran plasma digandingkan secara teraruh
REFERENCES
Cho,
B.C., Im, Y.H., Park, J.S., Jeong, T. & Hahn, Y.B. 2000. Fast Dry Etching
of Doped GaN Films in Cl2-Based Inductively
Coupled High Density Plasmas, Journal of the Korean Physical Society 37(1):
23-27.
Ledernez,
L., Olcaytug, F., Yasuda, H. & Urban, G. 2009. A Modification of Paschen
Law for Argon, 29th ICPIG, July Cancun, Mexico.
Lin,
Y.C., Chang, S J., Su, Y.K., Shei, S.C. & Hsu, S.J. 2003. Inductively
Coupled Plasma Etching of GaN Using Cl2/He
Gases. Materials Science and Engineering B 98(1): 60-64.
Oh,
C.S., Kim, T.H., Lim, K.Y. & Yang, J.W. 2004. GaN Etch Enhancement in
Inductively Coupled BCl3 Plasma
with the Addition of N2 and
SF6 Gas, Semicond. Sci. Technol.
19: 172-173.
Patrick,
V. 2007. Plasma Etching. Available at:
www.ccs.unicamp.br/cursos/fee107/download/cap10.pdf
Rosli,
S.A. & Abdul Aziz, A. 2005. Inductively Coupled Plasma Etching on GaN and
Its Related Materials, Regional Conferences of Solid State Science and
Technology, Kuantan, Pahang, Malaysia.
Sheu,
J.K., Su, Y.K., Chi, G.C., Jou, M.J., Liu, C.C., Chang, C.M. & Hung, W.C. 1999.
Inductively Coupled Plasma Etching of GaN Using Cl2/Ar
and Cl2/N2 Gases, Journal of Applied Physics 85(3): 1970-1974.
*Pengarang
untuk surat menyurat; email:sazlina.zm05@student.usm.my, lan@usm.my
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