Interface States and Barrier Heights on Metal/4H-SiC Interfaces

2009 ◽  
Vol 615-617 ◽  
pp. 427-430 ◽  
Author(s):  
Shaweta Khanna ◽  
Arti Noor ◽  
Man Singh Tyagi ◽  
Sonnathi Neeleshwar
Keyword(s):  
Work Function ◽  
Barrier Height ◽  
Surface Preparation ◽  
Interface States ◽  
Careful Examination ◽  
Barrier Heights ◽  
Metal Work Function ◽  
Wide Range ◽  
Metal Work ◽  
Density Of Interface 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.

scholarly journals Contacts to solution-synthesized SnS nanoribbons: dependence of barrier height on metal work function

Nanoscale ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 319-327 ◽  
Author(s):  
Jenifer R. Hajzus ◽  
Adam J. Biacchi ◽  
Son T. Le ◽  
Curt A. Richter ◽  
Angela R. Hight Walker ◽  
...  
Keyword(s):  
Work Function ◽  
Schottky Barrier ◽  
Barrier Height ◽  
Barrier Heights ◽  
Metal Work Function ◽  
Individual Solution ◽  
Specific Contact ◽  
Metal Work

Four different metals were patterned onto individual, solution-synthesized SnS nanoribbons to determine Schottky barrier heights and specific contact resistances.

New Technique for Ohmic Formation

1996 ◽  
Vol 427 ◽  
Author(s):  
S. Hara ◽  
T. Teraji ◽  
H. Okushi ◽  
K. Kajimura
Keyword(s):  
Work Function ◽  
Barrier Height ◽  
Electronic States ◽  
Surface States ◽  
Interface States ◽  
Hot Water ◽  
Flat Band ◽  
Interface Charges ◽  
The Difference ◽  
Density Of Interface States

AbstractWe propose a new systematical method to control Schottky barrier heights of metal/semiconductor interfaces by controlling the density of interface electronic states and the number of charges in the states. The density of interface states is controlled by changing the density of surface electronic states, which is controlled by surface hydrogenation and flattening the surface atomically. We apply establishing hydrogen termination techniques using a chemical solution, pH controlled buffered HF or hot water. Also, slow oxidation by oxygen gas was used to flatten resultant semiconductor surfaces. The density of interface charges is changeable by controlling a metal work function. When the density of surface states is reduced enough to unpin the Fermi level, the barrier height is determined simply by the difference between the work function of a metal φm and the flat-band semiconductor ØsFB. In such an interface with the low density of interface states, an Ohmic contact with a zero barrier height is formed when we select a metal with φm < φsFB. We have already demonstrated controlling Schottky and Ohmic properties by changing the pinning degree on silicon carbide (0001) surfaces. Further, on an atomically-flat Si(111) surface with monohydride termination, we have observed the lowering of an Al barrier height.

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

2012 ◽  
Vol 7 (1) ◽  
pp. 75 ◽  
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

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

2012 ◽  
Vol 717-720 ◽  
pp. 857-860 ◽  
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.

The influence of metal work function on the barrier heights of metal/pentacene junctions

2008 ◽  
Vol 103 (6) ◽  
pp. 063719 ◽  
Author(s):  
B. Jaeckel ◽  
J. B. Sambur ◽  
B. A. Parkinson
Keyword(s):  
Work Function ◽  
Barrier Heights ◽  
Metal Work Function ◽  
Metal Work

Low Schottky Barrier on N-Type Si for N-Channel Schottky Source/Drain MOSFETs

2003 ◽  
Vol 765 ◽  
Author(s):  
Meng Tao ◽  
Darshak Udeshi ◽  
Shruddha Agarwal ◽  
Nasir Basit ◽  
Eduardo Maldonado ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Atomic Scale ◽  
Barrier Heights ◽  
Metal Work Function ◽  
Metal Silicides ◽  
The Common ◽  
Work Functions ◽  
Metal Work ◽  
Density Of Interface States ◽  
The Ideal

AbstractSchottky source/drain (S/D) in Si-CMOS provide an alternative to current approaches in S/D, channel, and gate-stack engineering. The Schottky S/D PMOS has been demonstrated at a number of university and industrial laboratories. The bottleneck for the Schottky S/D NMOS is the fact that none of the common metals or metal silicides has a low enough barrier height (~0.2 eV) on n-type Si. A method to produce low Schottky barriers on n-type Si with common metals including aluminum (Al) and chromium (Cr) is reported in this paper. The interface between metal and Si(100) is engineered at the atomic scale with a monolayer of selenium (Se) to reduce the density of interface states, and the engineered interface shows inertness to chemical and electronic processes at the interface. One consequence of this electronic inertness is that the Schottky barrier is now more dependent on the metal work function. Al and Cr both have work functions very close to the Si electron affinity. It is found that the Schottky barrier of Al on Se-engineered n-type Si(100) is 0.08 eV, and that of Cr is 0.26 eV. These numbers agree well with the ideal Schottky barrier heights for Al and Cr on n-type Si(100), but are significantly different from the barrier heights known for four decades for these metals on n-type Si(100). These results bring new hope for the Schottky S/D NMOS with a metal commonly used in the Si industry.

Sign in / Sign up

Export Citation Format

Share Document