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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

Schematics of the cross-sectional view of the conventional (a) and self-align gate (b) HFETs.
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Figure 3: Schematics of the cross-sectional view of the conventional (a) and self-align gate (b) HFETs.

Mentions: As an evaluation method for the gate-first process, we fabricated AlGaN/GaN HFETs with ohmic metals which were deposited first followed by the deposition of gate electrodes. The deposited ohmic and gate electrodes were then annealed together by changing the annealing temperature and annealing time. The schematic of the cross-sectional view of the HFETs for evaluation is shown in Figure 3a. The device fabrication started with the isolation of the mesa, which was formed by inductively coupled plasma (ICP) with an etching depth of 100 nm. The following processes were similar with the fabrication of Schottky diode mentioned above. The TiN film (about 200 nm) was formed under a N2/Ar sputtering gas with ratio (nitrogen percentage) of 3:15 (15%). After that, a cap layer of W/Au (30/70 nm) was deposited on the TiN layer in Ar ambient to reduce the gate resistance. The gate length and gate-source/drain spacing of the TiN/W/Au-gated AlGaN/GaN HFET were 3 and 3 μm, respectively.


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)

Schematics of the cross-sectional view of the conventional (a) and self-align gate (b) HFETs.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Schematics of the cross-sectional view of the conventional (a) and self-align gate (b) HFETs.
Mentions: As an evaluation method for the gate-first process, we fabricated AlGaN/GaN HFETs with ohmic metals which were deposited first followed by the deposition of gate electrodes. The deposited ohmic and gate electrodes were then annealed together by changing the annealing temperature and annealing time. The schematic of the cross-sectional view of the HFETs for evaluation is shown in Figure 3a. The device fabrication started with the isolation of the mesa, which was formed by inductively coupled plasma (ICP) with an etching depth of 100 nm. The following processes were similar with the fabrication of Schottky diode mentioned above. The TiN film (about 200 nm) was formed under a N2/Ar sputtering gas with ratio (nitrogen percentage) of 3:15 (15%). After that, a cap layer of W/Au (30/70 nm) was deposited on the TiN layer in Ar ambient to reduce the gate resistance. The gate length and gate-source/drain spacing of the TiN/W/Au-gated AlGaN/GaN HFET were 3 and 3 μm, respectively.

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