SEMICONDUCTOR MATERIALS

A photoluminescence study of plasma reactive ion etching-induced damage in GaN

Z. Mouffak1, , A. Bensaoula2 and L. Trombetta3

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 Corresponding author: Z. Mouffak, Email:zmouffak@csufresno.edu

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Abstract: GaN films with reactive ion etching (RIE) induced damage were analyzed using photoluminescence (PL). We observed band-edge as well as donor-acceptor peaks with associated phonon replicas, all in agreement with previous studies. While both the control and damaged samples have their band-edge peak location change with temperature following the Varshni formula, its intensity however decreases with damage while the D-A peak increases considerably. Nitrogen post-etch plasma was shown to improve the band edge peak and decrease the D-A peak. This suggests that the N2 plasma has helped reduce the number of trapped carriers that were participating in the D-A transition and made the D°X transition more active, which reaffirms the N2 post-etch plasma treatment as a good technique to heal the GaN surface, most likely by filling the nitrogen vacancies previously created by etch damage.

Key words: GaNetch damagephotoluminescencereactive ion etching



[1]
Nakamura S, Mukai T, Senoh M. Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes. Appl Phys Lett, 1994, 64:1687 doi: 10.1063/1.111832
[2]
Popovici G. Group Ⅲ nitride semiconductor compounds, physics and applications. Gil B, ed. Oxford:Clarendon Press, 1999
[3]
Wu Y F, Keller P B, Kapolnek D, et al. Very high breakdown voltage and large transconductance realized on GaN heterojunction field effect transistors. Appl Phys Lett, 1996, 69:1438 doi: 10.1063/1.117607
[4]
Morkoç H, Strite S, Gao G B, et al. Large-band-gap SiC, Ⅲ-Ⅴ nitride, and Ⅱ-Ⅵ ZnSe-based semiconductor device technologies. J Appl Phys, 1994, 76:1363 doi: 10.1063/1.358463
[5]
Morkoç H. Nitride semiconductors and devices. Springer, Berlin, Heidelberg:Springer Series in Material Science, 1999 doi: 10.1007/978-3-642-58562-3.pdf
[6]
Pearton S J, Vartuli C B, Zolper J C, et al. Ion implantation doping and isolation of GaN. Appl Phys Lett, 1995, 67:1435 doi: 10.1063/1.114518
[7]
Strite S, Morkoç H. GaN, AlN, and InN:a review. J Vac Sci Technol B, 1992, 10:1237 doi: 10.1116/1.585897
[8]
Goldenberg B, Zook J D, Ulmer R J. Ultraviolet and violet light-emitting GaN diodes grown by low-pressure metalorganic chemical vapor deposition. Appl Phys Lett, 1993, 62:381 doi: 10.1063/1.108963
[9]
Mouffak Z, Medelci-Djezzar N, Boney C, et al. Effect of photo-assisted RIE damage on GaN. MRS Internet J Nitride Semicond Res, 2003, 8:7 doi: 10.1557/S1092578300000508
[10]
Mouffak Z, Bensaoula A, Trombetta L. Temperature dependence of the energy gap in semiconductors. J Appl Phys, 2004, 95:727 doi: 10.1063/1.1632552
[11]
Hwang S J, Cho Y H, Song J J, et al. Photoluminescence excitation study of LO-phonon assisted excitonic transitions in GaN. MRS Proceedings, 1997, 482:691 doi: 10.1557/PROC-482-691
[12]
Fischer S, Wetzel C, Haller E E, et al. On p-type doping in GaN-acceptor binding energies. Appl Phys Lett, 1995, 67:1298 doi: 10.1063/1.114403
[13]
Götz W, Johnson N M, Chen C, et al. Activation energies of Si donors in GaN. Appl Phys Lett, 1996, 68:3144 doi: 10.1063/1.115805
[14]
Philippe A. Electro-optical characterization of hexagonal and cubic gallium nitride for blue emitters application. PhD Dissertation, Institut National des Sciences Appliquées (INSA) de Lyon, 1999
[15]
Varshni Y P. Temperature dependence of the energy gap in semiconductors. Physica, 1967, 34:149 doi: 10.1016/0031-8914(67)90062-6
[16]
Monemar B. Fundamental energy gap of GaN from photoluminescence excitation spectra. Phys Rev B, 1974, 10:676 doi: 10.1103/PhysRevB.10.676
[17]
Gil B, Briot O, Aulombard R L. Valence-band physics and the optical properties of GaN epilayers grown onto sapphire with wurtzite symmetry. Phys Rev B, 1995, 52:17028 doi: 10.1103/PhysRevB.52.R17028
[18]
Merz C, Kunzer M, Kaufmann U. Free and bound excitons in thin wurtzite GaN layers on sapphire. Semicond Sci Tech, 1996, 11:712 doi: 10.1088/0268-1242/11/5/010
[19]
Xu S J, Liu W, Li M F. Direct determination of free exciton binding energy from phonon-assisted luminescence spectra in GaN epilayers. Appl Phys Lett, 2002, 81:2959 doi: 10.1063/1.1514391
Fig. 1.  Photoluminescence spectra of the control sample at 10 K. The log scale spectrum is also shown. Yellow luminescence is not very visible in this sample.

Fig. 2.  Identification of different peaks from the photoluminescence spectra of the control sample at 10 K (from Fig. 1). The log scale makes it easy to see the different recombinations.

Fig. 3.  Photoluminescence spectra at different temperatures of the control part of sample A (n-GaN). We observe a red shift of the band-edge peak with increasing temperatures, due to the decrease of the bandgap with increasing temperature, and a blue shift of the D-A peak due to a thermal filling of some defect level with increasing temperatures.

Fig. 4.  Photoluminescence spectra at different temperatures of the etched part of sample A. Here there is also a noticeable red shift of the band-edge peak with increasing temperatures, and there is a blue shift of the D-A peak due to a thermal filling of some defect level with increasing temperatures.

Fig. 5.  Temperature dependence of the band-edge transition in the control part and the damaged part of sample A.

Fig. 6.  Temperature dependence of the donor-acceptor peak energy in the control part and damaged part of the GaN sample.

Fig. 7.  PL spectra at 14 K of a damaged sample (etched at 200 W for 20 s in BCl$_{3}$/Cl$_{2}$/N$_{2})$, a damaged sample (etched the same way) post treated with N$_{2}$ plasma, and a control sample. Damage decreases the intensity of the main peak and increases the D-A peak, which becomes more important. Post-etch N$_{2}$ plasma partially restores the band edge luminescence and decreases the defect density.

[1]
Nakamura S, Mukai T, Senoh M. Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes. Appl Phys Lett, 1994, 64:1687 doi: 10.1063/1.111832
[2]
Popovici G. Group Ⅲ nitride semiconductor compounds, physics and applications. Gil B, ed. Oxford:Clarendon Press, 1999
[3]
Wu Y F, Keller P B, Kapolnek D, et al. Very high breakdown voltage and large transconductance realized on GaN heterojunction field effect transistors. Appl Phys Lett, 1996, 69:1438 doi: 10.1063/1.117607
[4]
Morkoç H, Strite S, Gao G B, et al. Large-band-gap SiC, Ⅲ-Ⅴ nitride, and Ⅱ-Ⅵ ZnSe-based semiconductor device technologies. J Appl Phys, 1994, 76:1363 doi: 10.1063/1.358463
[5]
Morkoç H. Nitride semiconductors and devices. Springer, Berlin, Heidelberg:Springer Series in Material Science, 1999 doi: 10.1007/978-3-642-58562-3.pdf
[6]
Pearton S J, Vartuli C B, Zolper J C, et al. Ion implantation doping and isolation of GaN. Appl Phys Lett, 1995, 67:1435 doi: 10.1063/1.114518
[7]
Strite S, Morkoç H. GaN, AlN, and InN:a review. J Vac Sci Technol B, 1992, 10:1237 doi: 10.1116/1.585897
[8]
Goldenberg B, Zook J D, Ulmer R J. Ultraviolet and violet light-emitting GaN diodes grown by low-pressure metalorganic chemical vapor deposition. Appl Phys Lett, 1993, 62:381 doi: 10.1063/1.108963
[9]
Mouffak Z, Medelci-Djezzar N, Boney C, et al. Effect of photo-assisted RIE damage on GaN. MRS Internet J Nitride Semicond Res, 2003, 8:7 doi: 10.1557/S1092578300000508
[10]
Mouffak Z, Bensaoula A, Trombetta L. Temperature dependence of the energy gap in semiconductors. J Appl Phys, 2004, 95:727 doi: 10.1063/1.1632552
[11]
Hwang S J, Cho Y H, Song J J, et al. Photoluminescence excitation study of LO-phonon assisted excitonic transitions in GaN. MRS Proceedings, 1997, 482:691 doi: 10.1557/PROC-482-691
[12]
Fischer S, Wetzel C, Haller E E, et al. On p-type doping in GaN-acceptor binding energies. Appl Phys Lett, 1995, 67:1298 doi: 10.1063/1.114403
[13]
Götz W, Johnson N M, Chen C, et al. Activation energies of Si donors in GaN. Appl Phys Lett, 1996, 68:3144 doi: 10.1063/1.115805
[14]
Philippe A. Electro-optical characterization of hexagonal and cubic gallium nitride for blue emitters application. PhD Dissertation, Institut National des Sciences Appliquées (INSA) de Lyon, 1999
[15]
Varshni Y P. Temperature dependence of the energy gap in semiconductors. Physica, 1967, 34:149 doi: 10.1016/0031-8914(67)90062-6
[16]
Monemar B. Fundamental energy gap of GaN from photoluminescence excitation spectra. Phys Rev B, 1974, 10:676 doi: 10.1103/PhysRevB.10.676
[17]
Gil B, Briot O, Aulombard R L. Valence-band physics and the optical properties of GaN epilayers grown onto sapphire with wurtzite symmetry. Phys Rev B, 1995, 52:17028 doi: 10.1103/PhysRevB.52.R17028
[18]
Merz C, Kunzer M, Kaufmann U. Free and bound excitons in thin wurtzite GaN layers on sapphire. Semicond Sci Tech, 1996, 11:712 doi: 10.1088/0268-1242/11/5/010
[19]
Xu S J, Liu W, Li M F. Direct determination of free exciton binding energy from phonon-assisted luminescence spectra in GaN epilayers. Appl Phys Lett, 2002, 81:2959 doi: 10.1063/1.1514391
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    Received: 26 May 2014 Revised: 10 July 2014 Online: Published: 01 November 2014

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      Z. Mouffak, A. Bensaoula, L. Trombetta. A photoluminescence study of plasma reactive ion etching-induced damage in GaN[J]. Journal of Semiconductors, 2014, 35(11): 113003. doi: 10.1088/1674-4926/35/11/113003 Z. Mouffak, A. Bensaoula, L. Trombetta. A photoluminescence study of plasma reactive ion etching-induced damage in GaN[J]. J. Semicond., 2014, 35(11): 113003. doi: 10.1088/1674-4926/35/11/113003.Export: BibTex EndNote
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      Z. Mouffak, A. Bensaoula, L. Trombetta. A photoluminescence study of plasma reactive ion etching-induced damage in GaN[J]. Journal of Semiconductors, 2014, 35(11): 113003. doi: 10.1088/1674-4926/35/11/113003

      Z. Mouffak, A. Bensaoula, L. Trombetta. A photoluminescence study of plasma reactive ion etching-induced damage in GaN[J]. J. Semicond., 2014, 35(11): 113003. doi: 10.1088/1674-4926/35/11/113003.
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      A photoluminescence study of plasma reactive ion etching-induced damage in GaN

      doi: 10.1088/1674-4926/35/11/113003
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      • Corresponding author: Z. Mouffak, Email:zmouffak@csufresno.edu
      • Received Date: 2014-05-26
      • Revised Date: 2014-07-10
      • Published Date: 2014-11-01

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