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Nanoscale electro-structural characterisation of ohmic contacts formed on p-type implanted 4H-SiC.

Frazzetto A, Giannazzo F, Lo Nigro R, Di Franco S, Bongiorno C, Saggio M, Zanetti E, Raineri V, Roccaforte F - Nanoscale Res Lett (2011)

Bottom Line: In particular, the surface roughness of the Al-implanted SiC regions annealed at 1700°C could be strongly reduced using a protective carbon capping layer during annealing.This latter resulted in an improved surface morphology and specific contact resistance of the Ti/Al ohmic contacts formed on these regions.The microstructure of the contacts was monitored by X-ray diffraction analysis and a cross-sectional transmission electron microscopy, and correlated with the electrical results.

View Article: PubMed Central - HTML - PubMed

Affiliation: Consiglio Nazionale delle Ricerche-Istituto per la Microelettronica e Microsistemi-Strada VIII, n, 5, Zona Industriale, 95121, Catania, Italy. fabrizio.roccaforte@imm.cnr.it.

ABSTRACT
This work reports a nanoscale electro-structural characterisation of Ti/Al ohmic contacts formed on p-type Al-implanted silicon carbide (4H-SiC). The morphological and the electrical properties of the Al-implanted layer, annealed at 1700°C with or without a protective capping layer, and of the ohmic contacts were studied using atomic force microscopy [AFM], transmission line model measurements and local current measurements performed with conductive AFM.The characteristics of the contacts were significantly affected by the roughness of the underlying SiC. In particular, the surface roughness of the Al-implanted SiC regions annealed at 1700°C could be strongly reduced using a protective carbon capping layer during annealing. This latter resulted in an improved surface morphology and specific contact resistance of the Ti/Al ohmic contacts formed on these regions. The microstructure of the contacts was monitored by X-ray diffraction analysis and a cross-sectional transmission electron microscopy, and correlated with the electrical results.

No MeSH data available.


Related in: MedlinePlus

AFM image of the Al+-implanted 4H-SiC surface "as-implanted" sample. Scan area of 20 × 20 μm2.
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Figure 1: AFM image of the Al+-implanted 4H-SiC surface "as-implanted" sample. Scan area of 20 × 20 μm2.

Mentions: First, AFM was used to monitor the morphological properties of the Al+-implanted regions. An AFM image taken over an area of 20 × 20 μm2 for the 'as-implanted' sample is reported in Figure 1. As can be seen, before annealing at high temperature, the as-implanted sample exhibits a quite flat surface, with a mean surface roughness value (root mean square, RMS) of 1.14 nm. It is worth noting that this RMS value is comparable to that of the mean surface roughness in 'non-implanted' samples.


Nanoscale electro-structural characterisation of ohmic contacts formed on p-type implanted 4H-SiC.

Frazzetto A, Giannazzo F, Lo Nigro R, Di Franco S, Bongiorno C, Saggio M, Zanetti E, Raineri V, Roccaforte F - Nanoscale Res Lett (2011)

AFM image of the Al+-implanted 4H-SiC surface "as-implanted" sample. Scan area of 20 × 20 μm2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211209&req=5

Figure 1: AFM image of the Al+-implanted 4H-SiC surface "as-implanted" sample. Scan area of 20 × 20 μm2.
Mentions: First, AFM was used to monitor the morphological properties of the Al+-implanted regions. An AFM image taken over an area of 20 × 20 μm2 for the 'as-implanted' sample is reported in Figure 1. As can be seen, before annealing at high temperature, the as-implanted sample exhibits a quite flat surface, with a mean surface roughness value (root mean square, RMS) of 1.14 nm. It is worth noting that this RMS value is comparable to that of the mean surface roughness in 'non-implanted' samples.

Bottom Line: In particular, the surface roughness of the Al-implanted SiC regions annealed at 1700°C could be strongly reduced using a protective carbon capping layer during annealing.This latter resulted in an improved surface morphology and specific contact resistance of the Ti/Al ohmic contacts formed on these regions.The microstructure of the contacts was monitored by X-ray diffraction analysis and a cross-sectional transmission electron microscopy, and correlated with the electrical results.

View Article: PubMed Central - HTML - PubMed

Affiliation: Consiglio Nazionale delle Ricerche-Istituto per la Microelettronica e Microsistemi-Strada VIII, n, 5, Zona Industriale, 95121, Catania, Italy. fabrizio.roccaforte@imm.cnr.it.

ABSTRACT
This work reports a nanoscale electro-structural characterisation of Ti/Al ohmic contacts formed on p-type Al-implanted silicon carbide (4H-SiC). The morphological and the electrical properties of the Al-implanted layer, annealed at 1700°C with or without a protective capping layer, and of the ohmic contacts were studied using atomic force microscopy [AFM], transmission line model measurements and local current measurements performed with conductive AFM.The characteristics of the contacts were significantly affected by the roughness of the underlying SiC. In particular, the surface roughness of the Al-implanted SiC regions annealed at 1700°C could be strongly reduced using a protective carbon capping layer during annealing. This latter resulted in an improved surface morphology and specific contact resistance of the Ti/Al ohmic contacts formed on these regions. The microstructure of the contacts was monitored by X-ray diffraction analysis and a cross-sectional transmission electron microscopy, and correlated with the electrical results.

No MeSH data available.


Related in: MedlinePlus