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Synthesis of titanium nitride for self-aligned gate AlGaN/GaN heterostructure field-effect transistors.

Li L, Nakamura R, Wang Q, Jiang Y, Ao JP - Nanoscale Res Lett (2014)

Bottom Line: The Schottky barrier height of the TiN on n-GaN is around 0.5 to 0.6 eV and remains virtually constant with varying nitrogen ratios.The results of annealing evaluation at different temperatures and duration times show that the TiN/W/Au gate stack can withstand the ohmic annealing process at 800°C for 1 or 3 min.Finally, the self-aligned TiN-gated AlGaN/GaN heterostructure field-effect transistors are obtained with good pinch-off characteristics.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Technology and Science, The University of Tokushima, Tokushima 770-8506, Japan.

ABSTRACT
In this study, titanium nitride (TiN) is synthesized using reactive sputtering for a self-aligned gate process. The Schottky barrier height of the TiN on n-GaN is around 0.5 to 0.6 eV and remains virtually constant with varying nitrogen ratios. As compared with the conventional Ni electrode, the TiN electrode presents a lower turn-on voltage, while its reverse leakage current is comparable with that of Ni. The results of annealing evaluation at different temperatures and duration times show that the TiN/W/Au gate stack can withstand the ohmic annealing process at 800°C for 1 or 3 min. Finally, the self-aligned TiN-gated AlGaN/GaN heterostructure field-effect transistors are obtained with good pinch-off characteristics.

No MeSH data available.


Related in: MedlinePlus

AFM images of the TiN films deposited with various nitrogen percentages. (a) 0%, (b) 15%, (c) 40%, and (d) 85%.
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Figure 1: AFM images of the TiN films deposited with various nitrogen percentages. (a) 0%, (b) 15%, (c) 40%, and (d) 85%.

Mentions: The typical atomic force microscope (AFM) images of the TiN samples were recorded in tapping mode in an area of 20 × 20 μm2 (Figure 1). Amorphous surface morphologies are represented in all the samples. The root-mean-square surface roughness are about 2.29,1.73, 0.38, 0.48, 0.53, and 0.71 nm for the films with nitrogen percentage of 0%, 5%, 15%, 40%, 60%, and 85%, respectively, which indicates that the films deposited with a mediate nitrogen content show a relatively smoother surface. The actual nitrogen contents of the samples determined from the X-ray photoelectron spectroscopy (XPS) data are 80.49%, 84.50%, 87.20%, 85.62%, and 82.06% for the samples with nitrogen deposition gas percentages of 5%, 15%, 40%, 60%, and 85%, respectively. These results show that all of the TiN films are Ti-rich with similar actual nitrogen contents, except that the sample grown with 5% N2 has a slightly lower actual nitrogen content than the rest.


Synthesis of titanium nitride for self-aligned gate AlGaN/GaN heterostructure field-effect transistors.

Li L, Nakamura R, Wang Q, Jiang Y, Ao JP - Nanoscale Res Lett (2014)

AFM images of the TiN films deposited with various nitrogen percentages. (a) 0%, (b) 15%, (c) 40%, and (d) 85%.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4214824&req=5

Figure 1: AFM images of the TiN films deposited with various nitrogen percentages. (a) 0%, (b) 15%, (c) 40%, and (d) 85%.
Mentions: The typical atomic force microscope (AFM) images of the TiN samples were recorded in tapping mode in an area of 20 × 20 μm2 (Figure 1). Amorphous surface morphologies are represented in all the samples. The root-mean-square surface roughness are about 2.29,1.73, 0.38, 0.48, 0.53, and 0.71 nm for the films with nitrogen percentage of 0%, 5%, 15%, 40%, 60%, and 85%, respectively, which indicates that the films deposited with a mediate nitrogen content show a relatively smoother surface. The actual nitrogen contents of the samples determined from the X-ray photoelectron spectroscopy (XPS) data are 80.49%, 84.50%, 87.20%, 85.62%, and 82.06% for the samples with nitrogen deposition gas percentages of 5%, 15%, 40%, 60%, and 85%, respectively. These results show that all of the TiN films are Ti-rich with similar actual nitrogen contents, except that the sample grown with 5% N2 has a slightly lower actual nitrogen content than the rest.

Bottom Line: The Schottky barrier height of the TiN on n-GaN is around 0.5 to 0.6 eV and remains virtually constant with varying nitrogen ratios.The results of annealing evaluation at different temperatures and duration times show that the TiN/W/Au gate stack can withstand the ohmic annealing process at 800°C for 1 or 3 min.Finally, the self-aligned TiN-gated AlGaN/GaN heterostructure field-effect transistors are obtained with good pinch-off characteristics.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Technology and Science, The University of Tokushima, Tokushima 770-8506, Japan.

ABSTRACT
In this study, titanium nitride (TiN) is synthesized using reactive sputtering for a self-aligned gate process. The Schottky barrier height of the TiN on n-GaN is around 0.5 to 0.6 eV and remains virtually constant with varying nitrogen ratios. As compared with the conventional Ni electrode, the TiN electrode presents a lower turn-on voltage, while its reverse leakage current is comparable with that of Ni. The results of annealing evaluation at different temperatures and duration times show that the TiN/W/Au gate stack can withstand the ohmic annealing process at 800°C for 1 or 3 min. Finally, the self-aligned TiN-gated AlGaN/GaN heterostructure field-effect transistors are obtained with good pinch-off characteristics.

No MeSH data available.


Related in: MedlinePlus