Limits...
Nanoscale characterization of electrical transport at metal/3C-SiC interfaces.

Eriksson J, Roccaforte F, Reshanov S, Leone S, Giannazzo F, Lonigro R, Fiorenza P, Raineri V - Nanoscale Res Lett (2011)

Bottom Line: In this case, annealing at 500°C resulted in a reduction of the leakage current and an increase of the Schottky barrier height (from 0.77 to 1.12 eV).A structural analysis of the reaction zone carried out by transmission electron microscopy [TEM] and X-ray diffraction showed that the improved electrical properties can be attributed to a consumption of the surface layer of SiC due to silicide (Pt2Si) formation.The degradation of Schottky characteristics at higher temperatures (up to 900°C) could be ascribed to the out-diffusion and aggregation of carbon into clusters, observed by TEM analysis.

View Article: PubMed Central - HTML - PubMed

Affiliation: CNR-IMM, Strada VIII n, 5, Zona Industriale, 95121, Catania, Italy. jens.eriksson@imm.cnr.it.

ABSTRACT
In this work, the transport properties of metal/3C-SiC interfaces were monitored employing a nanoscale characterization approach in combination with conventional electrical measurements. In particular, using conductive atomic force microscopy allowed demonstrating that the stacking fault is the most pervasive, electrically active extended defect at 3C-SiC(111) surfaces, and it can be electrically passivated by an ultraviolet irradiation treatment. For the Au/3C-SiC Schottky interface, a contact area dependence of the Schottky barrier height (ΦB) was found even after this passivation, indicating that there are still some electrically active defects at the interface. Improved electrical properties were observed in the case of the Pt/3C-SiC system. In this case, annealing at 500°C resulted in a reduction of the leakage current and an increase of the Schottky barrier height (from 0.77 to 1.12 eV). A structural analysis of the reaction zone carried out by transmission electron microscopy [TEM] and X-ray diffraction showed that the improved electrical properties can be attributed to a consumption of the surface layer of SiC due to silicide (Pt2Si) formation. The degradation of Schottky characteristics at higher temperatures (up to 900°C) could be ascribed to the out-diffusion and aggregation of carbon into clusters, observed by TEM analysis.

No MeSH data available.


Related in: MedlinePlus

I-V spectroscopy, measured by C-AFM, and corresponding diode parameters. Localized forward (top) and reverse (bottom) I-V spectroscopy measured by C-AFM at 25 different tip locations on the Pt2Si contacts after annealing at 500°C (a), 700°C (b), and 900°C (c). The Schottky barrier heights (black, left axis) and leakage current densities taken at −3 V (red, right axis) extracted from I-V probe measurements for the different annealing temperatures are shown in (d).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211166&req=5

Figure 4: I-V spectroscopy, measured by C-AFM, and corresponding diode parameters. Localized forward (top) and reverse (bottom) I-V spectroscopy measured by C-AFM at 25 different tip locations on the Pt2Si contacts after annealing at 500°C (a), 700°C (b), and 900°C (c). The Schottky barrier heights (black, left axis) and leakage current densities taken at −3 V (red, right axis) extracted from I-V probe measurements for the different annealing temperatures are shown in (d).

Mentions: Figure 4 shows localized I-V spectroscopy measured by C-AFM at 25 different tip locations (separated by 1 μm) on the Pt2Si contacts after annealing at 500°C (a), 700°C (b), and 900°C (c). Increased local variations are observed under both forward (barrier height) and reverse (leakage currents) bias as the annealing temperature increases, consistent with the increasing presence of localized low-barrier patches at the contact interface. I-V characteristics were also measured in an electrical probe after each annealing step on circular diodes with radii of 20 and 100 μm, and the extracted diode parameters are summarized in Figure 4d. Already, the as-deposited Pt/3C-SiC(001) contacts exhibited improved electrical properties with respect to the Au/3C-SiC(001) system; the leakage current density (at −3 V) measured for Au and Pt diodes fabricated on the same wafer (sample B) reduced from 1 × 10−6 to 3 × 10−8 A/mm2. Moreover, the contact area dependence observed for the Au/3C-SiC system is absent for the Pt/SiC interface, suggesting better interface homogeneity. As can be seen in Figure 4d, the leakage current is slightly improved after annealing at 500°C compared to the as-deposited Pt, whereas a strong improvement of the Schottky barrier height (from 0.77 to 1.12 eV) is observed for this annealing temperature. At higher temperatures (700°C and 900°C), both the reverse and forward I-V characteristics begin to degrade.


Nanoscale characterization of electrical transport at metal/3C-SiC interfaces.

Eriksson J, Roccaforte F, Reshanov S, Leone S, Giannazzo F, Lonigro R, Fiorenza P, Raineri V - Nanoscale Res Lett (2011)

I-V spectroscopy, measured by C-AFM, and corresponding diode parameters. Localized forward (top) and reverse (bottom) I-V spectroscopy measured by C-AFM at 25 different tip locations on the Pt2Si contacts after annealing at 500°C (a), 700°C (b), and 900°C (c). The Schottky barrier heights (black, left axis) and leakage current densities taken at −3 V (red, right axis) extracted from I-V probe measurements for the different annealing temperatures are shown in (d).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211166&req=5

Figure 4: I-V spectroscopy, measured by C-AFM, and corresponding diode parameters. Localized forward (top) and reverse (bottom) I-V spectroscopy measured by C-AFM at 25 different tip locations on the Pt2Si contacts after annealing at 500°C (a), 700°C (b), and 900°C (c). The Schottky barrier heights (black, left axis) and leakage current densities taken at −3 V (red, right axis) extracted from I-V probe measurements for the different annealing temperatures are shown in (d).
Mentions: Figure 4 shows localized I-V spectroscopy measured by C-AFM at 25 different tip locations (separated by 1 μm) on the Pt2Si contacts after annealing at 500°C (a), 700°C (b), and 900°C (c). Increased local variations are observed under both forward (barrier height) and reverse (leakage currents) bias as the annealing temperature increases, consistent with the increasing presence of localized low-barrier patches at the contact interface. I-V characteristics were also measured in an electrical probe after each annealing step on circular diodes with radii of 20 and 100 μm, and the extracted diode parameters are summarized in Figure 4d. Already, the as-deposited Pt/3C-SiC(001) contacts exhibited improved electrical properties with respect to the Au/3C-SiC(001) system; the leakage current density (at −3 V) measured for Au and Pt diodes fabricated on the same wafer (sample B) reduced from 1 × 10−6 to 3 × 10−8 A/mm2. Moreover, the contact area dependence observed for the Au/3C-SiC system is absent for the Pt/SiC interface, suggesting better interface homogeneity. As can be seen in Figure 4d, the leakage current is slightly improved after annealing at 500°C compared to the as-deposited Pt, whereas a strong improvement of the Schottky barrier height (from 0.77 to 1.12 eV) is observed for this annealing temperature. At higher temperatures (700°C and 900°C), both the reverse and forward I-V characteristics begin to degrade.

Bottom Line: In this case, annealing at 500°C resulted in a reduction of the leakage current and an increase of the Schottky barrier height (from 0.77 to 1.12 eV).A structural analysis of the reaction zone carried out by transmission electron microscopy [TEM] and X-ray diffraction showed that the improved electrical properties can be attributed to a consumption of the surface layer of SiC due to silicide (Pt2Si) formation.The degradation of Schottky characteristics at higher temperatures (up to 900°C) could be ascribed to the out-diffusion and aggregation of carbon into clusters, observed by TEM analysis.

View Article: PubMed Central - HTML - PubMed

Affiliation: CNR-IMM, Strada VIII n, 5, Zona Industriale, 95121, Catania, Italy. jens.eriksson@imm.cnr.it.

ABSTRACT
In this work, the transport properties of metal/3C-SiC interfaces were monitored employing a nanoscale characterization approach in combination with conventional electrical measurements. In particular, using conductive atomic force microscopy allowed demonstrating that the stacking fault is the most pervasive, electrically active extended defect at 3C-SiC(111) surfaces, and it can be electrically passivated by an ultraviolet irradiation treatment. For the Au/3C-SiC Schottky interface, a contact area dependence of the Schottky barrier height (ΦB) was found even after this passivation, indicating that there are still some electrically active defects at the interface. Improved electrical properties were observed in the case of the Pt/3C-SiC system. In this case, annealing at 500°C resulted in a reduction of the leakage current and an increase of the Schottky barrier height (from 0.77 to 1.12 eV). A structural analysis of the reaction zone carried out by transmission electron microscopy [TEM] and X-ray diffraction showed that the improved electrical properties can be attributed to a consumption of the surface layer of SiC due to silicide (Pt2Si) formation. The degradation of Schottky characteristics at higher temperatures (up to 900°C) could be ascribed to the out-diffusion and aggregation of carbon into clusters, observed by TEM analysis.

No MeSH data available.


Related in: MedlinePlus