Capacitance behavior of InAlN Schottky diodes in presence of large concentrations of shallow and deep states related to oxygen

Abstract

Articles you may be interested inHigh-resolution X-ray diffraction analysis of AlxGa1−xN/InxGa1−xN/GaN on sapphire multilayer structures: Theoretical, simulations, and experimental observationsThe capacitance-voltage-temperature characteristics of nonintentionally doped In 0.16 Al 0.84 N/n þ -GaN Schottky diodes were measured at 1 MHz and in the 90-400 K range. They are discussed in the framework of existing theories, which properly treat the Poisson's equation, especially near the edge of the space-charge region, the so-called transition region. The concentration of a shallow donor and of a deep DX-like center, previously reported, is properly determined. The key parameter to discuss the temperature dependence of the capacitance is the ratio between the frequency of the small ac modulating signal and the temperature-dependent emission rate associated to each level. The capacitance-voltage C-V a curves were successfully fitted using a three parameters expression over the full range of temperatures. The concentration of both shallow and deep levels exceeds a few 10 18 cm À3 . Based on secondary ion mass spectrometry profiling, we assign both levels to the dominant oxygen impurity. This result supports our previous assignment of the shallow donor to a substitutional oxygen atom on a nitrogen site and the deep state to an O-related DX center, naturally explaining its high concentration. The sluggish kinetics at low temperatures, associated to the large concentration of deep levels located near the transition region, is illustrated by hysteresis loops in the C-V a curves below 270 K. Furthermore, the contribution of free carriers to the capacitance is revealed below 150 K, when both shallow and deep donors cannot respond anymore due to an emission rate lower than the 1 MHz modulating frequency. Finally, the presence of a highly doped thin surface barrier, as already reported in other III-nitrides, finds further support. V C 2015 AIP Publishing LLC. [http://dx.

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“…These C-V trends and the bi-directional hysteresis under reverse bias can also be attributed to the existence of the deep-level states and interface states [47][48][49]. In light of these results, it can be concluded that -1.25 V < Vb < -2.1V reverse voltage range is the optimum voltage range for the operation of the photodiode with high responsivity.…”

Hot electron induced non-saturation current behavior at high electric field in InAlN/GaN heterostructures with ultrathin barrier

“…Since the GaN buffer is the same between the AlGaN/GaN and InAlN/GaN heterostructure, the donor may exist in the InAlN layer or interface. It should be mentioned that there are also other defect states with deeper level existing in the InAlN layer or interface, as revealed by capacitance-voltage and deep-level transient spectroscopy experiments8212223. The donor defect with an activation energy of 90 meV exhibited by the temperature-dependence Hall measurement is just the most easily excited by the high temperature and contributes to the sheet density.…”

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“…Growth studies have concentrated on morphology, microstructure, and impurities, [6][7][8][9][10][11] and n-and p-type doping. 5,12) In devices, AlInN has been primarily used in high-electron-mobility transistors, 7,8) for high index contrast layer in distributed Bragg reflectors, 9,10,12) as functional layers in LEDs or LDs, [13][14][15][16] thermoelectricity, 17) and solar-blind photodetectors. 5,13,18) There have been no reports of using AlInN in a power diode.…”