The Roles of Threading Dislocations on Electrical Properties of AlGaN/GaN Heterostructure Grown by MBE

Abstract

The role played by different types of threading dislocations ͑TDs͒ on the electrical properties of AlGaN/GaN heterostructure grown by plasma-assisted molecular beam epitaxy ͑MBE͒ was investigated. Samples with different defect structures and densities were prepared and measurements were taken from the same sample to study the correlative behavior of various TDs. From the Hall measurement, the electron mobility in two-dimensional electron gas channel was mainly controlled by the edge dislocation, which has a dominant amount in the material. The edge TDs acted as Coulomb scattering centers inside the channel and reduces the carrier mobility and increased its resistance. Screw TDs played a much significant role than edge TDs in determining the reverse-bias leakage current of Schottky barrier diodes. Leakage current is affected slightly by the reduction of free carrier density in the channel for samples with a higher edge TD density, but screw TD, which acted as the current leakage path, was more deleterious to the reverse-bias leakage current of AlGaN/GaN structure.

Exploring an Approach toward the Intrinsic Limits of GaN Electronics

“…Generally speaking, it has been predicted that the electrical properties of GaN are strongly affected by threading dislocations, namely, screw and edge dislocations. , For example, screw dislocations generally generate current leakage paths. Therefore, it is crucial to significantly reduce the density of screw dislocations in order to minimize leakage current in GaN. , Edge dislocations are likely to accommodate any unintentional acceptor impurities. As a result, edge dislocations with a reasonably high density can effectively suppress leakage current .…”

“…Therefore, it is crucial to significantly reduce the density of screw dislocations in order to minimize leakage current in GaN. , Edge dislocations are likely to accommodate any unintentional acceptor impurities. As a result, edge dislocations with a reasonably high density can effectively suppress leakage current . The GaN grown on our HT AlN in a 2D growth mode aligns with the two requirements.…”

High-Temperature Atomic Layer Deposition of GaN on 1D Nanostructures

“…This mechanism also explains why the resistivity of the HTALD GaN in this study is lower with the inclusion of buffer layers, where less compensation from point defects and dislocations gives way to higher conductivity. We further suggest that the inclusion of buffer layers reduces threading dislocations (TD) that have been shown to increase the resistivity of GaN [89]. Edge-type TD escalate compensation in GaN, which increases its resistivity and photoconductivity [90].…”

Screw threading dislocations in AlN: Structural and electronic properties of In and O doped material

“…Both models are predicted to act as leakage current pathways, inhibiting optimum performance of microelectronic devices and elucidating recent experimental observations in MBE grown AlGaN/GaN heterostructures where screw dislocations dominated leakage currents in Schottky barrier diodes. 26 In the metal In-filled core model, the bandgap of AlN is drastically altered due to the introduction of multiple Inrelated levels. A variety of states filling the AlN bandgap is also revealed for the InN and In and O filled core models.…”