Correlation of Metal‐Semiconductor Barrier Height and Metal Work Function; Effects of Surface States

Available data on Schottky barrier heights on silicon and carbon rich faces of 4H-SiC have been carefully analyzed to investigate the mechanism of barrier formation on these surfaces. As in case of 3C and 6H-SiC, the barrier heights depend strongly upon method of surface preparation with a considerable scatter in the barrier height for a given metal-semiconductor system. However, for each metal the barrier height depends on the metal work function and strong pinning of the Fermi level has not been observed. The slopes of the linear relation between the barrier heights and metal work functions varies over a wide range from 0.2 to about 0.75 indicating that the density of interface states depends strongly on the method of surface preparation. By a careful examination of the data on barrier heights we could identify a set of nearly ideal interfaces in which the barrier heights vary linearly with metal work function approaching almost to the Schottky limit. The density of interface states for these interfaces is estimated to lie between 4.671012 to 2.631012 states/ cm2 eV on the silicon rich surface and about three times higher on the carbon rich faces. We also observed that on these ideal interfaces the density of interface states was almost independent of metal indicating that the metal induced gap states (MIGS) play no role in determining the barrier heights in metal-4H-SiC Schottky barriers.

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Metal work-function-dependent barrier height of Ni contacts with metal-embedded nanoparticles to 4H-SiC

Nanoscale Research Letters ◽

10.1186/1556-276x-7-75 ◽

2012 ◽

Vol 7 (1) ◽

pp. 75 ◽

Cited By ~ 16

Author(s):

Min-Seok Kang ◽

Jung-Joon Ahn ◽

Kyoung-Sook Moon ◽

Sang-Mo Koo

Keyword(s):

Work Function ◽

Barrier Height ◽

Metal Work Function ◽

Embedded Nanoparticles ◽

Metal Work

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

Japanese Journal of Applied Physics ◽

10.7567/jjap.57.04fg13 ◽

2018 ◽

Vol 57 (4S) ◽

pp. 04FG13 ◽

Cited By ~ 8

Author(s):

Hiroyoshi Imadate ◽

Tomoyoshi Mishima ◽

Kenji Shiojima

Keyword(s):

Work Function ◽

Schottky Barrier ◽

Barrier Height ◽

Schottky Barrier Height ◽

Schottky Contacts ◽

Electrical Characteristics ◽

Free Standing ◽

Metal Work Function ◽

Metal Work

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Metal Work-function and Doping-Concentration Dependent Barrier Height of Ni-Contacts to 4H-SiC with Metal-Embedded Nano-Particles

Materials Science Forum ◽

10.4028/www.scientific.net/msf.717-720.857 ◽

2012 ◽

Vol 717-720 ◽

pp. 857-860 ◽

Cited By ~ 3

Author(s):

Min Seok Kang ◽

Jung Ho Lee ◽

Anders Hallén ◽

Carl Mikael Zetterling ◽

Wook Bahng ◽

...

Keyword(s):

Work Function ◽

Barrier Height ◽

Doping Concentration ◽

Electrical Contacts ◽

Nano Particles ◽

Ag Nps ◽

Au Nps ◽

Metal Work Function ◽

Metal Work ◽

Au Nano Particles

We investigated the effect of the metal work-function and doping concentration on the barrier height of Ni-contacts with embedded nano-particles (NPs) on 4H-SiC surfaces. Both n-type epitaxial layers with ND=1×1016 cm-3, and layers doped by phosphorous implantation to a doping concentration of ~1×1019 cm-3 are used. The barrier height is reduced with increasing doping concentration and the silver (Ag) nano-particles (R~18.5 nm) further enhances the local electric field of the electrical contacts to 4H-SiC in comparison to gold (Au) nano-particles (R~20.2 nm). In the case of ion-implanted samples, the barrier height of the fabricated SiC diode structures with embedded Ag-NPs was significantly reduced by ~0.09 eV and ~0.25 eV compared to the samples with Au-NPs and the sample without NPs, respectively.

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