A comparison of the Hall-effect and secondary ion mass spectroscopy on the shallow oxygen donor in unintentionally doped GaN films

We report on temperature-dependent Hall-effect measurements and secondary ion mass spectroscopy on unintentionally doped, n-type conducting GaN epitaxial films. Over a wide range of free carrier concentrations we find a good correlation between the Hall measurements and the atomic oxygen concentration. We observe an increase of the oxygen concentration close to the interface between the film and the sapphire substrate, which is typical for the growth technique used (synthesis from galliumtrichloride and ammonia). It produces a degenerate n-type layer of ≈1.5 μm thickness and results in a temperature-independent mobility and Hall concentration at low temperatures (<50 K). The gradient in free carrier concentration can also be seen in spatially resolved Raman and cathodoluminescence experiments. Based on the temperature dependence of the Hall-effect, Fourier transform infrared absorption experiments, and photoluminescence we come to the conclusion that oxygen produces a shallow donor level with a binding en...

[1]  L. Romano,et al.  Hall-effect analysis of GaN films grown by hydride vapor phase epitaxy , 1998 .

[2]  David C. Look,et al.  Degenerate layer at GaN/sapphire interface: Influence on Hall-effect measurements , 1997 .

[3]  Lester F. Eastman,et al.  The role of dislocation scattering in n-type GaN films , 1998 .

[4]  C. Kuo,et al.  ACTIVATION ENERGIES OF SI DONORS IN GAN , 1996 .

[5]  L. Romano,et al.  Electronic and structural properties of GaN grown by hydride vapor phase epitaxy , 1996 .

[6]  R. Nieminen,et al.  Ab initio study of oxygen point defects in GaAs, GaN, and AlN. , 1996, Physical review. B, Condensed matter.

[7]  D. Bimberg,et al.  Scanning cathodoluminescence microscopy: A unique approach to atomic‐scale characterization of heterointerfaces and imaging of semiconductor inhomogeneities , 1991 .

[8]  Characteristic of InGaN/GaN Laser Diode Grown by a Multi-Wafer MOCVD System , 1999 .

[9]  A. Hoffmann.  Optical properties of GaN , 1997 .

[10]  Van de Walle CG,et al.  Atomic geometry and electronic structure of native defects in GaN. , 1994, Physical review. B, Condensed matter.

[11]  F. G. McIntosh,et al.  Impurity dependence on hydrogen and ammonia flow rates in InGaN bulk films , 1997 .

[12]  Briggs,et al.  Native defects in gallium nitride. , 1995, Physical review. B, Condensed matter.

[13]  L. Romano,et al.  Thickness Dependence of Electronic Properties of GaN Epi-layers , 1996 .

[14]  F. Ren,et al.  Electrical passivation in hydrogen plasma exposed GaN , 1994 .

[15]  Tanakorn Osotchan,et al.  Electron mobilities in gallium, indium, and aluminum nitrides , 1994 .

[16]  V. Riede,et al.  On the origin of free carriers in high‐conducting n‐GaN , 1983 .

[17]  C. Kuo,et al.  Shallow and deep level defects in GaN , 1995 .

[18]  B. Meyer,et al.  Residual Donors in GaN Epitaxial Films - A Correlation of HALL Effect, SIMS and Photoluminescence Data , 1997 .

[19]  Michael Schmidt,et al.  On the nature of the 3.41 eV luminescence in hexagonal GaN , 1998 .

[20]  David C. Look,et al.  Dislocation Scattering in GaN , 1999 .

[21]  H. K. Ng,et al.  Magneto‐optical studies of GaN and GaN/AlxGa1−xN: Donor Zeeman spectroscopy and two dimensional electron gas cyclotron resonance , 1996 .

[22]  S. Denbaars,et al.  Accurate mobility and carrier concentration analysis for GaN , 1997 .

[23]  Robert M. Fletcher,et al.  Hall-effect characterization of III–V nitride semiconductors for high efficiency light emitting diodes , 1999 .

[24]  Theeradetch Detchprohm,et al.  Shallow donors in GaN—The binding energy and the electron effective mass , 1995 .