Failure Mechanism of Ti/TiN/Pt Ohmic Contacts to n-type 4H-SiC after High Temperature Annealing Treatment in Air

AbstractBy using TDEAT and ammonia gas, MOCVD TiN films were grown at 300°C and 30torr.After annealing in a vacuum furnace at 500°C, 550°C, and 600°C, the TiN films were investigated by transmission electron microscopy (TEM). After annealing at 550°C, both hexagonal and cubic AIN phase were found at the interface between Al and TiN films. A Ti rich phase such as Al3Ti was also found at Al side. The failure mechanism during high temperature annealing is discussed.

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Ni-Based Ohmic Contacts to Silicon Carbide Examined by Electron Microscopy

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.186.82 ◽

2012 ◽

Vol 186 ◽

pp. 82-85 ◽

Cited By ~ 1

Author(s):

Marek Wzorek ◽

Andrzej Czerwiński ◽

Andrian V. Kuchuk ◽

Jacek Ratajczak ◽

Ania Piotrowska ◽

...

Keyword(s):

Electron Microscopy ◽

Silicon Carbide ◽

High Temperature ◽

Phase Transformations ◽

Formation Mechanism ◽

Ohmic Contacts ◽

Contact Layer ◽

Contact Structures ◽

High Temperature Annealing ◽

Annealing Step

Ni/Si multilayer contact structures to 4H-SiC after subsequent annealing steps are investigated with electron microscopy methods. After high temperature annealing step, specific defects in the contact structures are observed. The influence of phase transformations during annealings on the morphology on the contacts is discussed and the explanation of formation mechanism of voids within contact layer is proposed.

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Influence of High Temperature Annealing in Nitrogen on Upconversion Luminescence of β-NaYF4: Yb3+, Er3+ Hexagonal Sub-Microplates

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.496.79 ◽

2012 ◽

Vol 496 ◽

pp. 79-83

Author(s):

Jun Wei Zhao ◽

Tie Kun Jia ◽

Xiang Gui Kong

Keyword(s):

High Temperature ◽

Sodium Citrate ◽

Hexagonal Phase ◽

Upconversion Luminescence ◽

Annealing Treatment ◽

Annealing Process ◽

High Temperature Annealing ◽

Nonradiative Relaxation ◽

Before And After ◽

Hydrothermal Methods

The pure β-NaYF4: Yb3+, Er3+ hexagonal sub-microplates were successfully prepared by the combination of coprecipitation and hydrothermal methods using sodium citrate as chelator. The size of them is about 600 nm × 400 nm (side length × thickness). The obtained sample was divided into two parts and one of them was annealed in nitrogen at 300 °C for 2 hours. The crystal structure of the β-NaYF4: Yb3+, Er3+ hexagonal sub-microplates before and after annealing treatment is hexagonal phase. Under the excitation of 980 nm diode laser, the upconversion luminescence intensity the sample after annealing is much stronger than that of the sample without annealing treatment. High temperature annealing process improved the crystallization of the sample, resulting in the decrease of the nonradiative relaxation and the enhancement of the upconversion luminescence.

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The Formation Mechanism of Ni-Based Ohmic Contacts to 4H-n-SiC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.717-720.833 ◽

2012 ◽

Vol 717-720 ◽

pp. 833-836 ◽

Cited By ~ 8

Author(s):

Andrian V. Kuchuk ◽

Krystyna Gołaszewska ◽

Vasyl P. Kladko ◽

M. Guziewicz ◽

Marek Wzorek ◽

...

Keyword(s):

High Temperature ◽

Electrical Transport ◽

Ohmic Contacts ◽

Structural Changes ◽

Specific Contact Resistance ◽

Main Role ◽

High Temperature Annealing ◽

Electrical Transport Properties ◽

Barrier Heights ◽

Specific Contact

In this work the electrical properties of Ni and Ni2Si contacts on n-type 4H-SiC were correlated to the strong structural changes at the contact/SiC interface upon annealing. We can conclude that only δ-Ni2Si grains play a main role in determining electrical transport properties of the Ni-based ohmic contacts to n-SiC. It is presumed that a recrystallization and texturization of δ-Ni2Si phase on (0001)SiC-surface during high temperature annealing (> 900°C) contributes to the change of barrier heights, as well as specific contact resistance of contacts.

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