Strain mapping of GaN substrates and epitaxial layers used for power electronic devices by synchrotron X-ray rocking curve topography

• Published in: Journal of crystal growth Vol. 583; no. C; p. 126559
• Main Authors: Liu, Yafei, Chen, Zeyu, Hu, Shanshan, Peng, Hongyu, Cheng, Qianyu, Raghothamachar, Balaji, Dudley, Michael
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2022; Elsevier BV; Elsevier
• Subjects: A1. Strain mapping; A3. Etching and regrowth; A3. Ion implantation; A3. Selective area doping; Annealing; B1. Nitrides; B3. Power electronic devices; Electronic devices; Epitaxial growth; Epitaxial layers; Etching; Gallium nitrides; Inductively coupled plasma; Strain distribution; Substrates; Synchrotron radiation; Synchrotrons; Topography; Vapor phase epitaxy; Vapor phases; Wafers; A3. Selective area doping; A3. Etching and regrowth; A1. Strain mapping; B3. Power electronic devices; A3. Ion implantation; B1. Nitrides
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2022.126559

•Strain and tilt maps of GaN materials are generated.•The strain and tilt maps of two kinds of GaN substrate are compared.•Annealing effect of the ion implanted GaN materials is studied.•The ICP etched and regrown GaN wafer show significant variations in strain values.•TBCl can remove some damage from a preceding ICP etching process. Strain and tilt maps of gallium nitride (GaN) materials including substrates, ion-implanted and annealed epilayers, and etched and regrown epilayers by different etching methods have been generated from synchrotron X-ray rocking curve topography. The strain map of the ammonothermal grown GaN substrate shows uniform low strain values, while that of the patterned hydride vapor phase epitaxy (HVPE) grown substrate shows high strain centers as well as uniformly distributed low strain between them. Strain variations within the as-implanted wafers and the annealed wafers are similar, while the tilt levels are significantly decreased for the annealed wafers. The inductively coupled plasma (ICP) etched and then regrown sample gives rise to the significant variations in strain values within the imaged region, while using tertiary butyl chloride (TBCl) to etch the sample does not affect the strain distribution compared to the continuously grown sample without etching and can remove some damage from a preceding ICP etching process.