Excellent ohmic contact formation to undoped- AlGaNGaN heterostructures is achieved by the incorporation of silicon into TiAlMoAu metallization. Contact resistance and specific contact resistivity as low as 0.16 × mm and 6.77× 10-7 × cm2, respectively, have been obtained for the TiSiAlSiMoAu scheme. Transmission electron microscopy has revealed that the ohmic contact formation mechanism depends on the competing interfacial nitride and silicide formation reactions, the latter giving rise to improved contact performance. The formation and penetration of non-nitride reaction products of Si-containing Al-Au intermetallics to depths beyond the AlGaNGaN interface were observed. The superior ohmic performance of these schemes suggests that silicide-based low Schottky barrier contact formation may be preferable to an interfacial nitride contact mechanism in achieving improved ohmic behavior.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)