Electrical characteristics of n-GaN Schottky contacts on cleaved surfaces of free-standing substrates: Metal work function dependence of Schottky barrier height

We report the electrical characteristics of Schottky contacts with nine different metals (Ag, Ti, Cr, W, Mo, Au, Pd, Ni, and Pt) formed on clean m-plane surfaces by cleaving freestanding GaN substrates, compared with these of contacts on Ga-polar c-plane n-GaN surfaces grown on GaN substrates. The n-values from the forward current–voltage (I–V) characteristics are as good as 1.02–1.18 and 1.02–1.09 for the m- and c-plane samples, respectively. We found that the reverse I–V curves of both samples can be explained by the thermionic field emission theory, and that the Schottky barrier height of the cleaved m-plane contacts shows a metal work function dependence.

[1]  T. Kimoto,et al.  Nearly Ideal Current–Voltage Characteristics of Schottky Barrier Diodes Formed on Hydride-Vapor-Phase-Epitaxy-Grown GaN Free-Standing Substrates , 2010 .

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

[3]  M. Kuzuhara,et al.  I‐V and C‐V characteristics of rare‐earth‐metal/p‐GaN Schottky contacts , 2009 .

[4]  Takashi Shinohe,et al.  Reverse Characteristics of a 4H-SiC Schottky Barrier Diode , 2002 .

[5]  Hidetoshi Ishida,et al.  Nonpolar (11-20) plane AlGaN∕GaN heterojunction field effect transistors on (1-102) plane sapphire , 2007 .

[6]  Naoki Hara,et al.  High performance and high reliability AlGaN/GaN HEMTs , 2009 .

[7]  Bakshi,et al.  Soft-x-ray photoemission study of chemisorption and Fermi-level pinning at the Cs/GaAs(110) and K/GaAs(110) interfaces. , 1988, Physical review. B, Condensed matter.

[8]  T. Mukai,et al.  Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates , 2006 .

[9]  Y. Tokuda,et al.  A study on multiple defect states in low-carbon doped GaN layers and its correlation with AlGaN/GaN high electron mobility transistor operation , 2014 .

[10]  T. Mishima,et al.  Optical-Thermo-Transition Model of Reduction in On-Resistance of Small GaN p–n Diodes , 2013 .

[11]  Marc Ilegems,et al.  Infrared Lattice Vibrations and Free-Electron Dispersion in GaN , 1973 .

[12]  H. Morkoç,et al.  Low resistance ohmic contacts on wide band‐gap GaN , 1994 .

[13]  Mathew C. Schmidt,et al.  High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes , 2007 .

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

[15]  Naoki Hara,et al.  High‐power GaN‐HEMT with high three‐terminal breakdown voltage for W‐band applications , 2009 .

[16]  H. Amano,et al.  Facet dependence of leakage current and carrier concentration in m‐plane GaN Schottky barrier diode fabricated with MOVPE , 2017 .

[17]  T. Suemitsu,et al.  Correlation between current–voltage characteristics and dislocations evaluated with submicrometer Schottky contacts on n-GaN grown by metalorganic chemical vapor deposition , 2003 .

[18]  Joan M. Redwing,et al.  The role of the tunneling component in the current–voltage characteristics of metal-GaN Schottky diodes , 1998 .

[19]  Koji Katayama,et al.  Extremely Low On-Resistance and High Breakdown Voltage Observed in Vertical GaN Schottky Barrier Diodes with High-Mobility Drift Layers on Low-Dislocation-Density GaN Substrates , 2010 .

[20]  S. Kamiyama,et al.  Control of p-Type Conduction in a-Plane GaN Grown on Sapphire r-Plane Substrate , 2005 .

[21]  R. Fowler,et al.  The Analysis of Photoelectric Sensitivity Curves for Clean Metals at Various Temperatures , 1931 .

[22]  Hideki Hasegawa,et al.  Mechanism of anomalous current transport in n-type GaN Schottky contacts , 2002 .

[23]  T. Mishima,et al.  Electrical characteristics of Au/Ni Schottky diodes on cleaved m-plane surfaces of free-standing n-GaN substrates , 2015 .

[24]  Hadis Morkoç,et al.  Reactive ion etching of GaN using BCl3 , 1994 .

[25]  T. Kachi,et al.  A Vertical Insulated Gate AlGaN/GaN Heterojunction Field-Effect Transistor , 2007 .

[26]  S. Nakamura,et al.  Candela‐class high‐brightness InGaN/AlGaN double‐heterostructure blue‐light‐emitting diodes , 1994 .

[27]  R. Stratton,et al.  Field and thermionic-field emission in Schottky barriers , 1966 .

[28]  H. Amano,et al.  Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer , 1986 .

[29]  Toshihide Kikkawa,et al.  Highly Reliable 250 W GaN High Electron Mobility Transistor Power Amplifier , 2005 .

[30]  C. Carter,et al.  Schottky barriers on n-GaN grown on SiC , 1996 .

[31]  T. Mishima,et al.  High-Breakdown-Voltage and Low-Specific-on-Resistance GaN p–n Junction Diodes on Free-Standing GaN Substrates Fabricated Through Low-Damage Field-Plate Process , 2013 .