Reactive sputtering of III-N materials for applications in electronicdevices

Abstract

Gallium Nitride (GaN) and other III-N semiconductors are rapidly gainingimportance in high power and high frequency electronic applications. III-Nmaterial based devices are fabricated on heterostructures that are usually grownby high vacuum techniques such as metal-organic chemical vapor deposition(MOCVD) or molecular beam epitaxy (MBE). However, in many applications, it isnecessary to regrow thin cap layers of III-N materials during devicefabrication. One such application is regrowth of ohmic contacts to III-Ndevices. Heavily doped n⁺ GaN, or InGaN grown by MBE orMOCVD is used to obtain low resistance non-alloyed ohmic contacts to GaN baseddevices. However, from a commercial point of view, this becomes difficultbecause of the high cost and lack of availability of ultra high vacuum(∼1x10^-10 Torr) techniques in most clean roomfacilities. Reactive sputtering provides a cheaper and more ubiquitousalternative for the growth of thin cap layers on parent MOCVD III-Nheterostructures during device fabrication. In this work, we explore thepossibility of using reactive sputtering as a method to grow III-N materials asohmic contacts to GaN based devices.