Your Search Results

Use this resource - and many more! - in your textbook!

AcademicPub holds over eight million pieces of educational content for you to mix-and-match your way.

Experience the freedom of customizing your course pack with AcademicPub!
Not an educator but still interested in using this content? No problem! Visit our provider's page to contact the publisher and get permission directly.

Temperature Stability of AuGeNi Ohmic Contacts to GaAs

By: Shih, Yih-Cheng; Baker, J.; Murakami, M.; Callegari, A.; Lacey, D.;

1987 / IEEE / 444704779

Description

This item was taken from the IEEE Periodical ' Temperature Stability of AuGeNi Ohmic Contacts to GaAs ' To achieve reliable, thermally stable ohmic contacts to n-GaAs, surface preparation and thickness of the AuGeNi films must be properly chosen. In this work the contact resistance as a function of the alloying temperature cycle has been studied for different AuGeNi thickness and sputter cleaning conditions. In-situ X-ray photoemission spectroscopy (XPS) analysis of the sputter-cleaned GaAs-surface showed that the As2O3 was removed first, leaving a sputter damaged layer of GaAs containing 0.3 - 1 nm of Ga2O3. If a thin As2O3 layer was left on the surface, the contact resistance was large and non-uniform. At the optimum sputter cleaning conditions, when 5 nm of Ni was deposited first followed by 100 nm of AuGe, 30 nm of Ni and 50/100 nm of Au, the contact resistance was low and uniform with Rc¿0.1 ¿ - mm. Transmission electron microscope (TEM) analysis showed that a high density of uniform NiAs(Ge) grains at the GaAs interface is responsible for the much improved uniformity and thermal stability. Spread in contact resistance is due to the ß - AuGa phase contacting the GaAs.