Strain Recovery and Defect Characterization in Mg‐Implanted Homoepitaxial GaN on High‐Quality GaN Substrates

• Published in: Physica Status Solidi B. Basic Solid State Physics Vol. 257; no. 4
• Main Authors: Wang, Yekan, Huynh, Kenny, Liao, Michael E., Yu, Hsuan-Ming, Bai, Tingyu, Tweedie, James, Breckenridge, Mathew Hayden, Collazo, Ramon, Sitar, Zlatko, Bockowski, Michal, Liu, Yuzi, Goorsky, Mark S.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Blackwell (John Wiley & Sons) 01.04.2020
• Subjects: defects; GaN; implantation; Mg ions
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.201900705

The evolution of defects due to high‐pressure annealing of magnesium ion‐implanted epitaxial GaN grown on high‐quality GaN substrates is investigated. Changes in the implant‐induced strain are quantified as a function of annealing temperature and time. After annealing at 1300 °C for 10 min, the implant‐induced strain is fully relieved and accompanied by the presence of extended defects such as basal plane stacking faults and prismatic loops. Approximately one‐third of the original implant‐induced strain remains after annealing at 700 °C, and 5% of the original strain remains at 1000 °C for 100 min. In all cases, nearly all of the recovered strain occurs within first few minutes of annealing. A prominent increase in the asymmetric (101¯4) triple axis X‐ray rocking curve full width at 0.01 maximum (FW0.01M) is observed after annealing at 1300 °C for 10 min. After annealing at 1300 °C for 100 min, a subsequent decrease in FW0.01M is correlated with a reduction of the extended defect density from 4 × 108 to 3 × 107 cm−2, determined through transmission electron microscope (TEM) measurements. Further reduction in the density of the extended defects by optimizing annealing temperature and time is expected to improve the performance of GaN‐based vertical power devices. Herein, a series of novel characterization techniques is used to investigate the evolution of defects due to the high‐pressure annealing of magnesium ion‐implanted epitaxial GaN grown on high‐quality GaN substrates, as well as quantify the implant‐induced strain as a function of annealing temperature and annealing time.