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The formation of good Ohmic contacts to p-type silicon carbide (SiC) and gallium nitride (GaN) is an important physical and technological concern, because of the difficulty to find metals with low Schottky barriers to p-type wide band gap materials, and due to the high ionization energies of p-type dopant impurities. Typically, to overcome these issues, alloyed metallic compounds are used. In this work, the electrical properties of alloyed Ohmic contacts to p-type (Al-implanted) 4H-SiC and p-type (Mg-doped epilayers) GaN are presented and correlated with their microstructure. The impact of the surface preparation and annealing conditions are discussed, reporting the cases of Al/Ti contacts to p-SiC and Au/Ni contacts to p-GaN. The electrical characterization as a function of temperature allowed to define the dominant transport mechanism and to determine the barrier heights.
Trans Tech Publications Ltd
Publication date: 
1 Jan 2012

Fabrizio Roccaforte, Alessia Frazzetto, Giuseppe Greco, Raffaella Lo Nigro, Filippo Giannazzo, Michał Leszczyński, Pawel Prystawko, Edoardo Zanetti, Mario Saggio, Vito Raineri

Biblio References: 
Volume: 711 Pages: 203-207
Materials Science Forum