Effect of Carbon Doping and Crystalline Quality on the Vertical Breakdown Characteristics of GaN Layers Grown on 200-mm Silicon Substrates

• Published in: Journal of electronic materials 2015-10, Vol.44 (10), p.3272-3276
• Main Authors: Wang, W. Z., Selvaraj, S. L., Win, K. T., Dolmanan, S. B., Bhat, T., Yakovlev, N., Tripathy, S., Lo, G. Q.
• Format: Article
• Language: English
• Subjects: Carbon; Characterization and Evaluation of Materials; Chemistry and Materials Science; Crystallization; Electronics and Microelectronics; Instrumentation; Materials Science; Optical and Electronic Materials; Silicon; Solid State Physics; Studies
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-015-3832-3

We have carried out a systematic study on the vertical breakdown behavior of GaN-based epitaxial layers on 200-mm-diameter Si(111) substrates with different carbon concentrations. The GaN layers were grown by metalorganic chemical vapor deposition by tuning growth parameters such as temperature and pressure. This study shows that, when the carbon concentration of the wafers is below 1 × 10 18  cm −3 , the vertical leakage currents are high with breakdown voltages below 260 V. The wafers that reveal lower vertical leakage currents are those with moderate carbon doping concentrations (between ∼1 × 10 18  cm −3 and 2.5 × 10 18  cm −3 ), whereas wafers with higher carbon concentrations (≥4 × 10 18  cm −3 ) give rise to poor breakdown behavior caused by lower crystal quality and rougher surface morphology. The uniformity of vertical breakdown behavior across a 200-mm wafer shows that wafers with low crystal quality also exhibit poor uniformity. Moreover, when the carbon doping level is relatively high (between ∼2 × 10 18  cm −3 and 2.5 × 10 18  cm −3 ), good uniformity with variation of ∼5% can be achieved.