Metal Contacts on 
-GaN
T. U. Kampen, W. Mönch
Laboratorium fuer Festkoerperphysik, Gerhard-Mercator-Universitaet Duisburg
This article was received on June 2, 1996 and
accepted on December 16, 1996. Abstract
The Schottky barrier heights of silver and lead contacts on
n-type GaN (0001) epilayers were determined from current-voltage
characteristics. The zero-bias barrier heights and the ideality factors were
found to be linearly correlated. Similar observations were previously reported
for metal contacts on Si (111) and GaAs (110) surfaces. The barrier heights of
ideal Schottky contacts are characterized by image force lowering of the
barrier only. This gives an ideality factor of 1.01. From our data we obtain
barrier heights of 0.82 eV and 0.73eV for ideal Ag and Pb contacts on GaN,
respectively. The metal-induced gap states (MIGS) model predicts the barrier
heights of ideal Schottky contacts on a given semiconductor to be linearly
correlated with the electronegativities of the metals. The two important
parameters of this MIGS-and-electronegativity model are the charge neutrality
level (CNL) of the MIGS and a slope parameter. The CNL may be calculated from
the dielectric band gap and using the empirical tight-binding method. The slope
parameters are given by the optical dielectric constant of the respective
semiconductor. The predictions of the MIGS model for metal/GaN contacts are
confirmed by the results presented here and by barrier heights previously
reported by others for Au, Ti, Pt, and Pd contacts on GaN.Outline
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Cite this article as: MRS Internet J. Nitride Semicond. Res. 1, 41(1996).
last updated October 29, 1997 10:44:29 AM.© 1996-1997 The Materials Research Society
