Drift, diffusion, and trapping of hydrogen in p-type GaN

Using capacitance–voltage measurements we have measured both the diffusion and the field-induced drift of H in GaN p/n+ diodes grown by metalorganic vapor phase epitaxy. Our data are well described by a computational model which simulates all of the important electronic processes as well as the drift, diffusion, and trapping of hydrogen in the GaN lattice. The experimental data demonstrate that H exists in the positive charge state; they also suggest that hydrogen diffusivity is anisotropic in this hexagonal material. In the temperature range from ∼200 to 310 °C we have determined that the sum of the activation energies for diffusion and binding of H+ to magnesium acceptors is 2.03 eV. This is ∼0.6 eV larger than previous density functional theory estimates of this quantity. We present first-principles calculations which demonstrate the observed diffusion anisotropy and which suggest possible reasons why previous treatments underestimate the barrier for hydrogen diffusive motion.

[1]  R. Anderson,et al.  Two-step debonding of hydrogen from boron acceptors in silicon , 1991 .

[2]  Marvin L. Cohen,et al.  Electronic structure of solids , 1984 .

[3]  A. Zunger,et al.  Self-interaction correction to density-functional approximations for many-electron systems , 1981 .

[4]  G. Wahnström,et al.  Some tests of basic assumptions in transition state theory for hydrogen diffusion in FCC-metals , 1993 .

[5]  Alan Francis Wright,et al.  Theoretical description of H behavior in GaN p-n junctions , 2001 .

[6]  B. Vaandrager,et al.  Isotope effects on the rate of electron-beam dissociation of Mg-H complexes in GaN , 2002 .

[7]  Weber,et al.  Dissociation energies of shallow-acceptor-hydrogen pairs in silicon. , 1989, Physical review. B, Condensed matter.

[8]  Van de Walle CG,et al.  Hydrogen in GaN: Novel aspects of a common impurity. , 1995, Physical review letters.

[9]  S. Nakamura,et al.  Thermal Annealing Effects on P-Type Mg-Doped GaN Films , 1992 .

[10]  Frank S. Ham,et al.  Theory of diffusion-limited precipitation , 1958 .

[11]  William R. Wampler,et al.  Equilibrium state of hydrogen in gallium nitride: Theory and experiment , 2000 .

[12]  H. Mehrer Diffusion in Solid Metals and Alloys , 1990 .

[13]  A. F. Wright Influence of crystal structure on the lattice sites and formation energies of hydrogen in wurtzite and zinc-blende GaN , 1999 .

[14]  N. B. Smirnov,et al.  Fermi level dependence of hydrogen diffusivity in GaN , 2001 .

[15]  O. Brandt,et al.  Shallow donors in GaN studied by electronic Raman scattering in resonance with yellow luminescence transitions , 1996 .

[16]  R. J. Shul,et al.  GAN : PROCESSING, DEFECTS, AND DEVICES , 1999 .

[17]  S. Pearton,et al.  High Quality P‐Type GaN Deposition on c‐Sapphire Substrates in a Multiwafer Rotating‐Disk Reactor , 1995 .

[18]  G. Henkelman,et al.  A dimer method for finding saddle points on high dimensional potential surfaces using only first derivatives , 1999 .

[19]  Hannes Jonsson,et al.  Reversible work transition state theory: application to dissociative adsorption of hydrogen , 1995 .

[20]  L. Onsager Deviations from Ohm's Law in Weak Electrolytes , 1934 .

[21]  William R. Wampler,et al.  Diffusion, release, and uptake of hydrogen in magnesium-doped gallium nitride: Theory and experiment , 2001 .

[22]  R. Street,et al.  Activation of acceptors in Mg-doped GaN grown by metalorganic chemical vapor deposition , 1996 .