Magnesium diffusion profile in GaN grown by MOVPE

Abstract The diffusion of magnesium has been studied in GaN layers grown on sapphire substrate by atmospheric pressure metalorganic vapor-phase-epitaxy (MOVPE) in a “home-made” reactor. Secondary Ion Mass Spectroscopy (SIMS) was used to visualise the Mg profiles in two kinds of multi-sublayer GaN structures. One structure was grown with a variable flow of Ga precursor (TMG) and the second one with a variable growth temperature. In both cases, the Mg dopant precursor (Cp 2 Mg) flow was kept constant. Using the second Fick's law to fit the experimental SIMS data, we have deduced an increasing then a saturating Mg diffusion coefficient versus the Mg concentration. Mg incorporation was found to get higher for lower growth rate, i.e. when TMG flow is reduced. Furthermore, based on the temperature-related behaviour we have found that the activation energy for Mg diffusion coefficient in GaN was 1.9 eV. It is suggested that Mg diffuses via substitutional sites.

[1]  K. Kavanagh,et al.  Silicon diffusion at polycrystalline‐Si/GaAs interfaces , 1985 .

[2]  B. Jani,et al.  GaN property evolution at all stages of MOVPE Si/N treatment growth , 2007 .

[3]  Y. Chang,et al.  Study of Mg diffusion during metalorganic chemical vapor deposition of GaN and AlGaN , 1999 .

[4]  Isamu Akasaki,et al.  Photoluminescence of Mg-doped p-type GaN and electroluminescence of GaN p-n junction LED , 1991 .

[5]  S. Nakamura,et al.  Highly P-Typed Mg-Doped GaN Films Grown with GaN Buffer Layers , 1991 .

[6]  B. Jani,et al.  Modeling of laser reflectance evolution during metalorganic vapor phase epitaxy growth of GaN using SiN treatment , 2006 .

[7]  B. Jani,et al.  Effect of SiN treatment on GaN epilayer quality , 2003 .

[8]  A. Rebey,et al.  Diffusion of vanadium in GaAs , 2004 .

[9]  Daniel S. Green,et al.  Memory Effect and Redistribution of Mg into Sequentially Regrown GaN Layer by Metalorganic Chemical Vapor Deposition , 2003 .

[10]  Y. Ohba,et al.  A study on strong memory effects for Mg doping in GaN metalorganic chemical vapor deposition , 1994 .

[11]  J. Massies,et al.  Atomic structure of pyramidal defects in Mg-doped GaN , 2003 .

[12]  Gou-Chung Chi,et al.  The doping of GaN with Mg diffusion , 1999 .

[13]  B. Jani,et al.  Laser‐reflectometry monitoring of the GaN growth by MOVPE using SiN treatment: study and simulation , 2005 .

[14]  B. Jani,et al.  Correlation between morphological, electrical and optical properties of GaN at all stages of MOVPE Si/N treatment growth , 2006 .

[15]  B. Jani,et al.  Influence of silane flow on MOVPE grown GaN on sapphire substrate by an in situ SiN treatment , 2004 .

[16]  Shuji Nakamura,et al.  The Blue Laser Diode: GaN based Light Emitters and Lasers , 1997 .

[17]  Kenji Harafuji,et al.  Magnesium Diffusion at Dislocation in Wurtzite-Type GaN Crystal , 2005 .

[18]  S. Kamiyama,et al.  Simultaneous observation of luminescence and dissociation processes of Mg–H complex for Mg-doped GaN , 2002 .