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