Temperature dependent electrical studies on Cu/AlGaN/GaN Schottky barrier diodes with its microstructural characterization
KAUST DepartmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
Online Publication Date2019-07-20
Print Publication Date2019-07
Embargo End Date2021-07-20
Permanent link to this recordhttp://hdl.handle.net/10754/656205
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AbstractThe performance of the AlGaN/GaN heterostructure based devices depends largely upon electrical behavior of Schottky contact which controls the current flowing through the channel. In this work, electrical behavior of Copper (Cu) Schottky diodes on Al0.25Ga0.75N/GaN heterostructures grown on Silicon have been investigated using temperature dependent current-voltage (I-V) and capacitance-voltage (C-V) techniques. An ideality factor (η) of 1.3 at room temperature (RT) signified that the forward current is dominated by thermionic emission process for current flow in the Schottky diode. The strong polarization field effects with in the barrier layer of the strained AlGaN/GaN heterostructure were considered for evaluating the barrier height using C-V measurements. The barrier height from such analysis was found to be 1.66 eV at RT which is significantly higher than theoretically predicted barrier height for Cu/AlGaN/GaN Schottky diodes. This observation of high barrier height is attributed to the presence of an ultra-thin Cu2O layer between Cu and AlGaN layer as revealed from scanning transmission electron microscopy. The temperature dependence of the barrier height suggests inhomogeneous nature of the Cu/AlGaN/GaN interface with different level of barrier inhomogeneities in different temperature ranges. Further, frequency-dependent C-V measurements were used to electrically characterize surface traps at Cu/AlGaN/GaN interface. Present study highlights the potential of Cu as a Schottky contact on AlGaN/GaN heterostructures for achieving high barrier height which is of utmost importance in GaN based device technology.
CitationGarg, M., Kumar, A., Sun, H., Liao, C.-H., Li, X., & Singh, R. (2019). Temperature dependent electrical studies on Cu/AlGaN/GaN Schottky barrier diodes with its microstructural characterization. Journal of Alloys and Compounds, 806, 852–857. doi:10.1016/j.jallcom.2019.07.234
SponsorsManjari Garg is grateful to Council of Scientific and Industrial Research (CSIR) India for providing research fellowship. The authors would like Nanoscale Research Facility (NRF) at Indian Institute of Technology Delhi for allowing the I-V-T, C-V-T and C-f measurements. We would also thank Prof. Vinay Gupta, University of Delhi for deposition of Cu Schottky contacts on AlGaN/GaN heterostructures. The KAUST authors appreciate the support of KAUST Baseline BAS/1/1664-01-01, Competitive Research Grant URF/1/3437-01-01, GCC Research Council Grant REP/1/3189-01-01.
JournalJournal of Alloys and Compounds