Magnesium implant-activation in GaN: Impact of high-temperature annealing techniques on the state of implant induced defects and Mg activation (Conference Presentation)

The advancement in potential selective placement of p-GaN regions places the gallium nitride (GaN) material system on the forefront of next generation power semiconductor devices. The ion implantation technique is commonly used in fabrication of semiconductor devices to achieve high conductivity regions with successful demonstration for n-GaN. This technique has shown little success for post-Mg-implanted activation anneal to achieve p-GaN [1], largely due to the formation of substantial point defects as a result of the implant process. To activate Mg and repair these defects, high annealing temperatures of > 900 °C are required. Considering that GaN dissociates at 840 °C at atmospheric pressure, higher temperature annealing should be performed under a high overpressure of nitrogen and in combination with a protective cap layer. We report on the results of using a novel Gyrotron annealing technique for Mg implant-activation. Mg implanted GaN layers have been annealed at temperatures and pressures as high as 1300 °C and 40 bar respectively with and without a protective cap. It is observed that Gyrotron annealing at 1100 ˚C for 30 seconds eliminates secondary GaN (0004) Bragg peaks, due to stress relaxation. In addition, skew-symmetric x-ray rocking curves show no stress induced by annealing in the GaN (10-12) peak with FWHM of 59’’, although the GaN (30-32) peak is observed to broaden. We will present an extensive array of characterizations detailing results from Gyrotron annealing, conventional RTA, and high temperature (1300 °C) RTA on similar Mg-implanted, homoepitaxially grown GaN samples. [1] F. J. Kub et al. Electron. Lett., 50, 3 (2014): 197–198