Ion-Beam Induced Modifications of Titanium Schottky Barrier on 4H-SiC

2005 ◽  
Vol 483-485 ◽  
pp. 729-732 ◽  
Author(s):  
Fabrizio Roccaforte ◽  
Filippo Giannazzo ◽  
Corrado Bongiorno ◽  
Sebania Libertino ◽  
Francesco La Via ◽  
...  

The effects of ion irradiation on the Ti/4H-SiC Schottky barrier are discussed. The Ti/SiC interfacial region of test Schottky diodes was irradiated with 8 MeV Si+4 ions at fluences between 1×109 and 1×1012 ions/cm2. By increasing ion fluence, an increase of the Schottky barrier FB was observed, from FB=1.05 eV in the non-irradiated sample to FB =1.21 eV after irradiation at the highest fluence, accompanied by a decrease of the leakage current. Using different experimental analytical techniques enabled us to correlate the modification of the interfacial region with the contacts electrical behaviour. In particular, the structural and electrical modifications in the nearinterface region (different orientation of the Ti film, defects in the epilayer, dopant deactivation) were responsible for the change of the Ti barrier after irradiation.

2014 ◽  
Vol 2014 (HITEC) ◽  
pp. 000058-000060
Author(s):  
Tomas Hjort ◽  
Adolf Schöner ◽  
Andy Zhang ◽  
Mietek Bakowski ◽  
Jang-Kwon Lim ◽  
...  

Electrical characteristics of 4H-SiC Schottky barrier diodes, based on buried grid design are presented. The diodes, rated to 1200V/10A and assembled into high temperature capable TO254 packages, have been tested and studied up to 250°C. Compared to conventional SiC Schottky diodes, Ascatron's buried grid SiC Schottky diode demonstrates several orders of magnitude reduced leakage current at high temperature operation.


2014 ◽  
Vol 778-780 ◽  
pp. 828-831 ◽  
Author(s):  
Junichi Hasegawa ◽  
Kazuya Konishi ◽  
Yu Nakamura ◽  
Kenichi Ohtsuka ◽  
Shuhei Nakata ◽  
...  

We clarified the relationship between the enhanced leakage current of SiC Junction Barrier Schottky diodes and the stacking faults in the SiC crystal at the SiC and metal electrode interface by measuring the electrical and optical properties, and confirm by using the numerical simulations. Numerical simulation considering local lowering of Schottky barrier height, which is 0.8 eV lower than that of 4H-SiC well explained the 2-4 orders of magnitude higher reverse leakage current caused by the SFs. We concluded that the locally lowering of the Schottky barrier height at the 3C-SiC layer in the 4H-SiC surface is a main cause of the large reverse leakage current.


2006 ◽  
Vol 527-529 ◽  
pp. 1167-1170 ◽  
Author(s):  
Vito Raineri ◽  
Fabrizio Roccaforte ◽  
Sebania Libertino ◽  
Alfonso Ruggiero ◽  
V. Massimino ◽  
...  

The defects formation in ion-irradiated 4H-SiC was investigated and correlated with the electrical properties of Schottky diodes. The diodes were irradiated with 1 MeV Si+-ions, at fluences ranging between 1×109cm-2 and 1.8×1013cm-2. After irradiation, the current-voltage characteristics of the diodes showed an increase of the leakage current with increasing ion fluence. The reverse I-V characteristics of the irradiated diodes monitored as a function of the temperature showed an Arrhenius dependence of the leakage, with an activation energy of 0.64 eV. Deep level transient spectroscopy (DLTS) allowed to demonstrate that the Z1/Z2 center of 4H-SiC is the dominant defect in the increase of the leakage current in the irradiated material.


Author(s):  
Vito Raineri ◽  
Fabrizio Roccaforte ◽  
Sebania Libertino ◽  
Alfonso Ruggiero ◽  
V. Massimino ◽  
...  

2011 ◽  
Vol 20 (03) ◽  
pp. 417-422
Author(s):  
QUENTIN DIDUCK ◽  
IAN WALSH ◽  
DUBRAVKO BABIĆ ◽  
LESTER F. EASTMAN

We have found that Scandium metal is near ohmic as deposited on GaN , but when it is annealed at high temperatures a large barrier height Schottky forms. In this study we used Sc - Au contacts to form Schottky barrier diodes on AlGaN / GaN HEMT material. We have found that the morphology remains unchanged even after an 800 degrees centigrade anneal. This investigation has revealed that the reverse leakage current of this metal system is an order of magnitude lower than a conventional Ni - Au contact and supports a reverse breakdown that is 1/3rd larger. The similarity of the anneal temperatures to ohmic contacts enable gates and contacts to be annealed at the same time thus simplifying processing. The lack of morphology change supports the use of Sc - Au for E -beam alignment marks as well. Diode contacts on AlGaN / GaN with Schottky-ohmic separation of 10 microns demonstrated reverse breakdown in excess of 100V when the contacts were annealed at 800C. These results suggest this metallization may have applications as a new HEMT gate metal, and Schottky diodes.


Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1299 ◽  
Author(s):  
Santosh Kumar ◽  
Xiang Zhang ◽  
Vinay Kumar Mariswamy ◽  
Varra Rajagopal Reddy ◽  
Asokan Kandasami ◽  
...  

The irradiation effects of carbon and nitrogen medium energy ions (MEI) on charge transport, structural and optical properties of Ni/Pd/n-GaN Schottky barrier diodes are reported. The devices are exposed to 600 keV C2+ and 650 keV N2+ ions in the fluence range of 1 × 1013 to 1 × 1015 ions cm−2. The SRIM/TRIM simulations provide quantitative estimations of damage created along the trajectories of ion beams in the device profile. The electrical parameters like Schottky barrier height, series resistance of the Ni/Pd/n-GaN Schottky barrier diodes decreases for a fluence of 1 × 1013 ions cm−2 and thereafter increases with an increase in fluence of 600 keV C2+ and 650 keV N2+ ions. The charge transport mechanism is influenced by various current transport mechanisms along with thermionic emission. Photoluminescence studies have demonstrated the presence of yellow luminescence in the pristine samples. It disappears at higher fluences due to the possible occupancy of Ga vacancies. The presence of the green luminescence band may be attributed to the dislocation caused by the combination of gallium vacancy clusters and impurities due to MEI irradiation. Furthermore, X-ray diffraction studies reveal that there is a decrease in the intensity and shift in the diffraction peaks towards the lower side of two thetas. The reductions in the intensity of C2+ ion irradiation is more when compared to N2+ ion irradiation, which may be attributed to change in the mean atomic scattering factor on a given site for light C2+ ion as compared to N2+ ion.


1986 ◽  
Vol 71 ◽  
Author(s):  
K. Nauka ◽  
Jun Amano ◽  
M.P. Scott ◽  
E.R. Weber ◽  
J.E. Turner ◽  
...  

AbstractDeep level transient spectroscopy (DLTS) in conjunction with other analytical techniques was used to establish a correlation between the leakage current in the TiSi2/p+/n-Si shallow diodes (0.25 micron) and the Ti-related Ec - 0.23 eV deep trap. It was found that Ti diffused into the junction region durin the TiSi2 formation and caused leakage currents with values up to 2 × 10−8 A/cm2. Further increases of the leakage current were related to the formation of a TiSi2/n-Si Schottky barrier.


1998 ◽  
Vol 532 ◽  
Author(s):  
S. Coffa ◽  
S. Libertino ◽  
A. La Magna ◽  
V. Privitera ◽  
G. Mannino ◽  
...  

ABSTRACTThe results of several recent experiments aimed at assessing the room temperature migration properties of interstitials (D) and vacancies (V) in ion implanted crystalline Si are reviewed. We show that combining the results of ex-situ techniques (deep level transient spectroscopy and spreading resistance profilometry) and in-situ leakage current measurements new and interesting information can be achieved. It has been found that at room temperature I and V, generated by an ion beam, undergo fast long range migration (with diffusivities higher than 10−1 cm2/sec) which is interrupted by trapping at impurities (C, O) or dopant atoms and by recombination at surface. Analysis of two-dimensional migration of point defects injected through a photolithographically defined mask shows that a strong I recombination (characterized by a coefficient of 30 μm−1) occurs at the sample surface. Moreover, we have found that the strain field induced by an oxide or a nitride mask significantly affects defect migration and produces a strong anisotropy of the defect diffusivity tensor. Finally, using in-situ leakage current measuremens, performed both during and just after ion irradiation, the time scale of point defect evolution at room temperature has been determined and defect diffusivities evaluated. The implications of these results on our current understanding of defect and diffusion phenomena in Si are discussed.


2006 ◽  
Vol 517 ◽  
pp. 242-246
Author(s):  
C.K. Tan ◽  
Azlan Abdul Aziz ◽  
F.K. Yam ◽  
C.W. Lim ◽  
Hassan Zainuriah ◽  
...  

Pd Schottky diode exhibited stable rectifying behavior up to 500°C for 35 minutes in sequential annealing; with the Schottky barrier heights (SBHs), ΦB (I-V) of 0.6-0.7eV with the leakage current (LC) of 20 A at -5V. With the same range of SBHs, PdSi diodes were stable up to 500°C for 5 minutes with the LC of 0.182mA at -5V. The electrical characteristics obtained in this study are also compared with those obtained for Pd and PdSi Schottky diodes on p-GaN.


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