SI-IMPLANTATION ACTIVATION ANNEALING OF GAN UP TO 1400-DEGREES-C

Implant activation annealing of Si-implanted GaN is reported for tempe ratures from 1100 to 1400 degrees C. Free electron concentrations up t o 3.5 x 10(20) cm(-3) are estimated at the peak of the implanted profi le with Hall mobilities of similar to 60 cm(2)/Vs for annealing at 130 0 degrees C for 30 s with an AIN encapsulant layer. This mobility is c omparable to epitaxial GaN doped at a similarly high level. For anneal ing at greater than or equal to 1300 degrees C, the sample must be enc apsulated with AIN to prevent decomposition of the GaN layer. Channeli ng Rutherford backscattering demonstrates the partial removal of the i mplant damage after a 1400 degrees C anneal with a minimum channeling yield of 12.6% compared to 38.6% for the as-implanted spectrum. Scanni ng electron microscope images show evidence of decomposition of unenca psulated GaN after a 1300 degrees C anneal and complete sublimation af ter 1400 degrees C. The use of AIN encapsulation and annealing at temp eratures of similar to 1300 degrees C will allow the formation of sele ctive areas of highly doped GaN to reduce the contact and access resis tance in GaN-based transistors and thyristors.