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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