1. Time-Resolved Photocurrent Spectroscopic Diagnostics of Electrically Active Defects in AlGaN/GaN High Electron Mobility Transistor (HEMT) Structure Grown on Si Wafers
- Author
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Chungman Yang, Burcu Ozden, Mobbassar Hassan Sk, Vahid Mirkhani, Ayayi C. Ahyi, Michael C. Hamilton, Kosala Yapabandara, Minseo Park, Suhyeon Youn, Min P. Khanal, and Sangjong Ko
- Subjects
Materials science ,Electric current measurement ,Photocurrents ,Biomedical Engineering ,Bioengineering ,Algan gan ,02 engineering and technology ,High-electron-mobility transistor ,Field effect transistors ,Semiconducting aluminum compounds ,Time-resolved ,01 natural sciences ,Silicon wafers ,Electrically active defects ,High electron mobility transistors ,0103 physical sciences ,General Materials Science ,Wafer ,Spectroscopy ,010302 applied physics ,Photocurrent ,Electron mobility ,AlGaN/GaN high electron mobility transistors ,business.industry ,Gallium nitride ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Persistent Photoconductivity ,AlGaN/gaN ,Spectroscopic diagnostics ,Wavelength dependency ,Optoelectronics ,Defects ,Surface defects ,0210 nano-technology ,business ,Photocurrent generations - Abstract
Time-resolved photocurrent (TRPC) spectroscopy with a variable-wavelength sub-bandgap light excitation was used to study the dynamics of the decaying photocurrent generated in the heterostructures of the AlGaN/GaN high electron mobility transistors (HEMTs) layers. In AlGaN/GaN HEMTs, reliability of the device is degraded due to the prevalence of current collapse. It is recognized that electrically active deep level defects at the surface/interfaces and the bulk in the HEMTs layers can contribute to the unwanted current collapse effect. Therefore, it is of great importance to analyze the deep level defects if the reliability of the HEMTs device is to be improved. In this research, TRPC spectroscopy was used to elucidate the origin and nature of the deep level defects by analyzing the time evolution of the photocurrent decay excited at different wavelengths of light. The two devices that show similar characteristics for wavelength-dependency on photocurrent generation were chosen, and TRPC spectroscopy was conducted on these devices. Although the two samples show similar characteristics for the wavelength-dependency on photocurrent generation, they exhibited dissimilar time-dependent photocurrent decay dynamics. This implies that TRPC spectroscopy can be used to distinguish the traps which have different origins but have the same de-trapping energy. Scopus
- Published
- 2016
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