Correlation between current–voltage characteristics and dislocations for n-GaN Schottky contacts

We directly evaluated the effect of dislocations on current–voltage (I–V) characteristics of Au/Ni/n-GaN Schottky contacts. A submicrometer Schottky dot array was formed by electron beam lithography, and I–V measurements were conducted using atomic force microscopy with a conductive probe. The sample, which has a free electron concentration of 5.8×1017 cm−3, showed that neither dislocations nor steps affect the I–V characteristics. These results indicate that, in fabricating short-gate FETs, gate Schottky contacts containing dislocations should not be considered a problem with respect to uniformity and reproducibility.

[1]  T. C. McGill,et al.  Measurement of induced surface charges, contact potentials, and surface states in GaN by electric force microscopy , 1999 .

[2]  Motoaki Iwaya,et al.  Reduction of Etch Pit Density in Organometallic Vapor Phase Epitaxy-Grown GaN on Sapphire by Insertion of a Low-Temperature-Deposited Buffer Layer between High-Temperature-Grown GaN , 1998 .

[3]  James S. Speck,et al.  Electrical characterization of GaN p-n junctions with and without threading dislocations , 1998 .

[4]  E. C. Carr,et al.  CORRELATION OF CATHODOLUMINESCENCE INHOMOGENEITY WITH MICROSTRUCTURAL DEFECTS IN EPITAXIAL GAN GROWN BY METALORGANIC CHEMICAL-VAPOR DEPOSITION , 1997 .

[5]  Lester F. Eastman,et al.  Scattering of electrons at threading dislocations in GaN , 1998 .

[6]  W. Knap,et al.  GaN homoepitaxial layers grown by metalorganic chemical vapor deposition , 1999 .

[7]  Masahiko Sano,et al.  Violet InGaN/GaN/AlGaN-Based Laser Diodes with an Output Power of 420 mW , 1998 .

[8]  Ilesanmi Adesida,et al.  Metal contacts to n-type GaN , 1998 .

[9]  U. Mishra,et al.  Anisotropic epitaxial lateral growth in GaN selective area epitaxy , 1997 .

[10]  S. M. Sze,et al.  Physics of semiconductor devices , 1969 .

[11]  Akira Sakai,et al.  Thick GaN Epitaxial Growth with Low Dislocation Density by Hydride Vapor Phase Epitaxy , 1997 .

[12]  L. Romano,et al.  Study of Threading Dislocations in Wurtzite GaN Films Grown on Sapphire by Metalorganic Chemical Vapor Deposition , 1998 .

[13]  K. Shiojima.  Atomic force microscopy and transmission electron microscopy observations of KOH-etched GaN surfaces , 1999 .

[14]  Robert F. Davis,et al.  Dislocation density reduction via lateral epitaxy in selectively grown GaN structures , 1997 .

[15]  James S. Speck,et al.  Scanning capacitance microscopy imaging of threading dislocations in GaN films grown on (0001) sapphire by metalorganic chemical vapor deposition , 1998 .