Thickness Dependence on Interfacial and Electrical Properties in Atomic Layer Deposited AlN on c-plane GaN

Abstract

The interfacial and electrical properties of atomic layer deposited AlN on n-GaN with different AlN thicknesses were investigated. According to capacitance–voltage (C–V) characteristics, the sample with a 7.4-nm-thick AlN showed the highest interface and oxide trap densities. When the AlN thickness was 0.7 nm, X-ray photoelectron spectroscopy (XPS) spectra showed the dominant peak associated with Al–O bonds, along with no clear AlN peak. The amount of remained oxygen atoms near the GaN surface was found to decrease for the thicker AlN. However, many oxygen atoms were present across the AlN layer, provided the oxygen-related defects, which eventually increased the interface state density. The barrier inhomogeneity with thermionic emission (TE) model was appropriate to explain the forward bias current for the sample with a 7.4-nm-thick AlN, which was not proper for the sample with a 0.7-nm-thick AlN. The reverse leakage currents for both the samples with 0.7- and 7.4-nm-thick AlN were explained better using Fowler–Nordheim (FN) rather than Poole–Frenkel emissions.

Influence of Quantum-Well Width on the Electroluminescence Properties of AlGaN Deep Ultraviolet Light-Emitting Diodes at Different Temperatures

“…AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) can be widely used in the fields of solid-state lighting, medicine, biochemistry, and so on. Therefore, more and more efforts have been devoted to improve the crystal quality of the materials [ 1 – 4 ], the p-type doping techniques, and the optimization of the device structures [ 5 – 9 ]. Miyake et al demonstrated that the AlN crystal quality can be improved significantly by high-temperature annealing [ 3 ].…”

Improved drain lag by reduced surface current in GaN HEMT via an ultrathin HfO2 blanket layer

“…Similarly, Kim et al studied ALD AlN layers on GaN. They noted that trap densities of the 7.4 nm thick AlN layer were four times that of the 1.5 nm layer, while both samples displayed similar leakage characteristics [13]. Therefore, downscaling the gate dielectric thickness can be a promising compromise for improving transistor threshold stability, reliability characteristics, and transconductance.…”

Modification of contact properties in Pt/n-GaN Schottky junctions with ZnO and TiO2/ZnO interlayers

“…To modify the Schottky barrier height in vertical GaN Schottky junctions, the insertion of an ultrathin interlayer (IL) at the metal-semiconductor (MS) interface has been investigated using Al 2 O 3 [17], AlN [18], and ZnO [19]. Most importantly, ZnO/GaN heterojunctions have been investigated as high-sensitivity gas sensors [20,21] and photodetectors [22][23][24] as both GaN and ZnO have a hexagonal structure, a low lattice mismatch (∼1.8%), and similar bandgap energies [25].…”