Electrical Characterization of Traps in AlGaN/GaN FAT-HEMT’s on Silicon Substrate by C-V and DLTS Measurements

M. Charfeddine, Malek Gassoumi, H. Mosbahi, C. Gaquiére, M. A. Zaidi, H. Maaref

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DOI: 10.4236/jmp.2011.210152                

Abstract

We investigate high electron mobility transistors (HEMT’s) based on AlGaN/GaN grown by molecular beam epitaxy on Silicon substrates. The improvement of the performances of such transistors is still subject to the influence of threading dislocations and point defects which are commonly observed in these devices. Deep levels in FAT-HEMT’s are characterized by using Capacitance-Voltage (C-V) measurements, from which we can extract the barrier height and the donor concentration in the AlGaN layer. Deep Level Transient Spectroscopy (DLTS) Technique is also employed to identify defects in the heterostructure. Measurements reveal the presence of one electron trap with the activation energy E₁ = 0.30 eV and capture cross-section σ_n = 3.59 10^–19cm². The localization and the identification of this trap have been discussed.

Keywords

AlGaN/GaN, FAT-HEMT’s, C-V, Capacitance DLTS, Deep Level

Conflicts of Interest

The authors declare no conflicts of interest.

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