Ohmic Contacts for Extreme Bandgap Nitride Semiconductors

Nitride semiconductors with bandgaps near or above 5 eV offer tremendous promise for miniaturized power systems. However, an importa,nt fundamental challenge must be overcome to realize their full potential. Low-resistance ohmic contacts to these semiconductors are, difficult to form and must be further developed, requiring researchers to investigate and implement new strategies for ohmic contac,t formation. The Pennsylvania State University proposes to investigate the contact metallurgy for AlN and AlN-rich Al(Ga, In, Sc)N s,emiconductor alloys. Their methodology includes study of ternary and high-order phase equilibria, examination of the kinetics of rea,ction at metal/semiconductor interfaces, design and testing of new contact metallurgies, a combinatorial approach for optimizing the, most promising multilayer contacts, analysis of current transport, and characterization of the contact interface using microscopy a,nd spectroscopy. These approaches will inform studies of the mechanisms of ohmic contact formation and guide researchers to make imp,rovements. The program will be even more impactful because of a tight collaboration with Georgia Institute of Technology and Univers,ity of South Carolina where researchers are designing and growing extreme bandgap semiconductors and exploiting novel doping strateg,ies, grading of alloys, and heterostructures. The epilayers they are growing will be engineered to reduce the resistance of ohmic co,ntacts. The collaborative effort provides a wholistic approach to designing and engineering ohmic contacts to extreme bandgap semico,nductors that will improve not only high-voltage power electronics but also high-temperature electronics, high-power radio-frequency, electronics, and ultraviolet C laser diodes.